I forgot to send the details of this error:

<LogProperties>
<LogProperty><PropertyName>AssemblyVersion</PropertyName><PropertyValue>04.05.01</PropertyValue></LogProperty>
<LogProperty><PropertyName>PortalID</PropertyName><PropertyValue>0</PropertyValue></LogProperty>
<LogProperty><PropertyName>PortalName</PropertyName><PropertyValue>Portal CSN</PropertyValue></LogProperty>
<LogProperty><PropertyName>UserID</PropertyName><PropertyValue>1</PropertyValue></LogProperty>
<LogProperty><PropertyName>UserName</PropertyName><PropertyValue /></LogProperty>
<LogProperty><PropertyName>ActiveTabID</PropertyName><PropertyValue>37</PropertyValue></LogProperty>
<LogProperty><PropertyName>ActiveTabName</PropertyName><PropertyValue>Home</PropertyValue></LogProperty>
<LogProperty><PropertyName>RawURL</PropertyName><PropertyValue>/portalcsn/Home/tabid/37/ctl/Login/Default.aspx?returnurl=%2fPortalCSN%2fDefault.aspx</PropertyValue></LogProperty>
<LogProperty><PropertyName>AbsoluteURL</PropertyName><PropertyValue>/PortalCSN/Default.aspx</PropertyValue></LogProperty>
<LogProperty><PropertyName>AbsoluteURLReferrer</PropertyName><PropertyValue>http://aplep2.ti.petrobras.com.br/portalcsn/Home/tabid/37/ctl/Login/Default.aspx?returnurl=%2fPortalCSN%2fDefault.aspx</PropertyValue></LogProperty>
<LogProperty><PropertyName>UserAgent</PropertyName><PropertyValue>Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)</PropertyValue></LogProperty>
<LogProperty><PropertyName>DefaultDataProvider</PropertyName><PropertyValue>DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider</PropertyValue></LogProperty>
<LogProperty><PropertyName>ExceptionGUID</PropertyName><PropertyValue>d60a5cf9-03d3-404d-957c-612b62abb16e</PropertyValue></LogProperty>
<LogProperty><PropertyName>InnerException</PropertyName><PropertyValue>The type initializer for 'DotNetNuke.Entities.Profile.ProfileController' threw an exception.</PropertyValue></LogProperty>
<LogProperty><PropertyName>FileName</PropertyName><PropertyValue /></LogProperty>
<LogProperty><PropertyName>FileLineNumber</PropertyName><PropertyValue>0</PropertyValue></LogProperty>
<LogProperty><PropertyName>FileColumnNumber</PropertyName><PropertyValue>0</PropertyValue></LogProperty>
<LogProperty><PropertyName>Method</PropertyName><PropertyValue>System.Configuration.TypeUtil.GetTypeWithReflectionPermission</PropertyValue></LogProperty>
<LogProperty><PropertyName>StackTrace</PropertyName><PropertyValue /></LogProperty>
<LogProperty><PropertyName>Message</PropertyName><PropertyValue>DotNetNuke.Services.Exceptions.PageLoadException: The type initializer for 'DotNetNuke.Entities.Profile.ProfileController' threw an exception. ---&gt; System.TypeInitializationException: The type initializer for 'DotNetNuke.Entities.Profile.ProfileController' threw an exception. ---&gt; System.TypeInitializationException: The type initializer for 'DotNetNuke.Security.Profile.ProfileProvider' threw an exception. ---&gt; System.Configuration.ConfigurationErrorsException: An error occurred creating the configuration section handler for dotnetnuke/profiles: Could not load file or assembly 'DOTNETNUKE' or one of its dependencies. The account used is a computer account. Use your global user account or local user account to access this server. (Exception from HRESULT: 0x80070710) (\\s6000fs03\web\APL\PortalCSN\web.config line 18) ---&gt; System.IO.FileLoadException: Could not load file or assembly 'DOTNETNUKE' or one of its dependencies. The account used is a computer account. Use your global user account or local user account to access this server. (Exception from HRESULT: 0x80070710) File name: 'DOTNETNUKE' at System.Configuration.TypeUtil.GetTypeWithReflectionPermission(IInternalConfigHost host, String typeString, Boolean throwOnError) at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory.Init(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord) at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory.InitWithRestrictedPermissions(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord) at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory..ctor(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord) at System.Configuration.RuntimeConfigurationRecord.CreateSectionFactory(FactoryRecord factoryRecord) at System.Configuration.BaseConfigurationRecord.FindAndEnsureFactoryRecord(String configKey, Boolean&amp; isRootDeclaredHere) WRN: Assembly binding logging is turned OFF. To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There is some performance penalty associated with assembly bind failure logging. To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog]. --- End of inner exception stack trace --- at System.Configuration.BaseConfigurationRecord.FindAndEnsureFactoryRecord(String configKey, Boolean&amp; isRootDeclaredHere) at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object&amp; result, Object&amp; resultRuntimeObject) at System.Configuration.BaseConfigurationRecord.GetSection(String configKey, Boolean getLkg, Boolean checkPermission) at System.Configuration.BaseConfigurationRecord.GetSection(String configKey) at System.Web.Configuration.WebConfigurationManager.GetWebApplicationSection(String sectionName) at DotNetNuke.Framework.Providers.ProviderConfiguration.GetProviderConfiguration(String strProvider) at DotNetNuke.Framework.Reflection.CreateObject(String ObjectProviderType, String ObjectProviderName, String ObjectNamespace, String ObjectAssemblyName, Boolean UseCache) at DotNetNuke.Security.Profile.ProfileProvider.CreateProvider() at DotNetNuke.Security.Profile.ProfileProvider..cctor() --- End of inner exception stack trace --- at DotNetNuke.Security.Profile.ProfileProvider.Instance() at DotNetNuke.Entities.Profile.ProfileController..cctor() --- End of inner exception stack trace --- at DotNetNuke.Entities.Profile.ProfileController.GetUserProfile(UserInfo&amp; objUser) at DotNetNuke.Entities.Users.UserInfo.get_Profile() at DotNetNuke.Entities.Users.UserInfo.set_FirstName(String Value) at DotNetNuke.Security.Membership.AspNetMembershipProvider.FillUserInfo(Int32 portalId, IDataReader dr, Boolean isHydrated, Boolean CheckForOpenDataReader) at DotNetNuke.Security.Membership.AspNetMembershipProvider.GetUserByUserName(Int32 portalId, String username, Boolean isHydrated) at DotNetNuke.Security.Membership.AspNetMembershipProvider.UserLogin(Int32 portalId, String username, String password, String verificationCode, UserLoginStatus&amp; loginStatus) at DotNetNuke.Entities.Users.UserController.ValidateUser(Int32 portalId, String Username, String Password, String VerificationCode, String PortalName, String IP, UserLoginStatus&amp; loginStatus) at DotNetNuke.Modules.Admin.Security.Signin.cmdLogin_Click(Object sender, EventArgs e) at System.Web.UI.WebControls.Button.OnClick(EventArgs e) at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---</

Is there are reason you install 4.5.1 - did you upgrade to it?

Did you make sure web.config was well formed and merged together?

I tried googling this but there is very little information...

Tim what is your version? Can you provide more info if indeed this is the same issue?