My Site had been live for more than 4 years now. I am using DNN 4.5 I know it is old, but if it not broken don't fix it. So suddnly yesterday I got this error when I tried to open host setings:
Error: Host Settings is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: ResX input is not valid. Cannot find valid "resheader" tags for the ResX reader and writer type names. ---> System.Web.HttpParseException: ResX input is not valid. Cannot find valid "resheader" tags for the ResX reader and writer type names. ---> System.ArgumentException: ResX input is not valid. Cannot find valid "resheader" tags for the ResX reader and writer type names. at System.Resources.ResXResourceReader.ParseXml(XmlTextReader reader) at System.Resources.ResXResourceReader.EnsureResData() at System.Resources.ResXResourceReader.GetEnumerator() at System.Web.Compilation.BaseResourcesBuildProvider.GenerateResourceFile(AssemblyBuilder assemblyBuilder, IResourceReader reader) at System.Web.Compilation.BaseResourcesBuildProvider.GenerateCode(AssemblyBuilder assemblyBuilder) at System.Web.Compilation.AssemblyBuilder.AddBuildProvider(BuildProvider buildProvider) --- End of inner exception stack trace --- at System.Web.Compilation.AssemblyBuilder.AddBuildProvider(BuildProvider buildProvider) at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders() at System.Web.Compilation.BuildProvidersCompiler.PerformBuild() at System.Web.Compilation.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed) at System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories) at System.Web.Compilation.BuildManager.EnsureFirstTimeDirectoryInit(VirtualPath virtualDir) at System.Web.Compilation.BuildManager.GetBuildResultFromCacheInternal(String cacheKey, Boolean keyFromVPP, VirtualPath virtualPath, Int64 hashCode) at System.Web.Compilation.BuildManager.GetVPathBuildResultFromCacheInternal(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath) at System.Web.UI.TemplateControl.LoadControl(String virtualPath) at DotNetNuke.UI.Skins.Skin.InjectModule(Control objPane, ModuleInfo objModule, PortalSettings PortalSettings) --- End of inner exception stack trace ---

Also my UDT and Gallery is not working anymore.

Again I have not changed a thing, so why is not working and how to fix it. Thanks

I deleted DNN Site Map  an U Site Map through an FTP program becasue the issue stated with giving an error  saying that the DNN Site Map is using a different language then Reports, UDT and other Modules and the only way i can bring the site up is to delete Site Map using FTP. After I gained access to the site I went and deleted it from the Module Difinations page. I lost access to the host settings after that and Gallery doesn't work as well. The most frustrating part is UDT doesn't work anymore and I have a lot of pages using it. The error is "

DotNetNuke.Services.Exceptions.ModuleLoadException: ResX input is not valid. Cannot find valid "resheader" tags for the ResX reader and writer type names. ---> System.Web.HttpParseException: ResX input is not valid. Cannot find valid "resheader" tags for the ResX reader and writer type names. ---> System.ArgumentException: ResX input is not valid. Cannot find valid "resheader" tags for the ResX reader and writer type names. at System.Resources.ResXResourceReader.ParseXml(XmlTextReader reader) at System.Resources.ResXResourceReader.EnsureResData() at System.Resources.ResXResourceReader.GetEnumerator() at System.Web.Compilation.BaseResourcesBuildProvider.GenerateResourceFile(AssemblyBuilder assemblyBuilder, IResourceReader reader) at System.Web.Compilation.BaseResourcesBuildProvider.GenerateCode(AssemblyBuilder assemblyBuilder) at System.Web.Compilation.AssemblyBuilder.AddBuildProvider(BuildProvider buildProvider) --- End of inner exception stack trace --- at System.Web.Compilation.AssemblyBuilder.AddBuildProvider(BuildProvider buildProvider) at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders() at System.Web.Compilation.BuildProvidersCompiler.PerformBuild() at System.Web.Compilation.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed) at System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories) at System.Web.Compilation.BuildManager.EnsureFirstTimeDirectoryInit(VirtualPath virtualDir) at System.Web.Compilation.BuildManager.GetBuildResultFromCacheInternal(String cacheKey, Boolean keyFromVPP, VirtualPath virtualPath, Int64 hashCode) at System.Web.Compilation.BuildManager.GetVPathBuildResultFromCacheInternal(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.Compilation.BuildManager.GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile) at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath) at System.Web.UI.TemplateControl.LoadControl(String virtualPath) at DotNetNuke.UI.Skins.Skin.InjectModule(Control objPane, ModuleInfo objModule, PortalSettings PortalSettings) --- End of inner exception stack trace ---

Any idea of how to fix it without the upgrade would be much appreciated.
I wish I could upgrade but I am so scared of doing it. It is a very large site and when I first build it, I used the Original Blue DNN Skin but modified it to make it the skin for the site and I know when I upgrade it would over write it and I won't know how to fix it.
I tired to test it off line first but I never could get it to work, the upgrade I mean.
Thanks