We installed dnn 4.5.3 along with another ASP application in the same web root.  The server worked fine for a short period of time.  It now gets server crashes.  The event log has very little information.

AssemblyVersion: -1
PortalID: -1
PortalName:
UserID: -1
UserName:
ActiveTabID: -1
ActiveTabName:
RawURL:
AbsoluteURL:
AbsoluteURLReferrer:
UserAgent:
DefaultDataProvider:
ExceptionGUID:
InnerException: Value cannot be null. Parameter name: type
FileName:
FileLineNumber: -1
FileColumnNumber: -1
Method:
StackTrace:
Message: System.ArgumentNullException: Value cannot be null. Parameter name: type at System.Activator.CreateInstance(Type type, Boolean nonPublic) at DotNetNuke.Framework.Reflection.CreateObject(String TypeName, String CacheKey) at DotNetNuke.Services.Search.ModuleIndexer.GetModuleList(Int32 PortalID)
Source:
Server Name: LHI-WEBDMZ1

This was attempting to access the home/logon page.

Has anyone else seen intermittent server crashes that leave no trace?

An alternative solution is to open the DesktopModules table and look for a value of -1 in the SupportedFeatures column.  If you find a recored with a value of -1, then set the value to 0.