There is an issue with DNN where sometimes modules will get a bad value recorded for their supported features (like Searchable, Portable, etc).  This can cause the Search provider to try to create a the module's business class when it doesn't exist.  The easiest fix is to look in the database for bad values.  You'll want to look for a -1 in the SupportedFeatures column in the DesktopModules table, change it to a 0.  Run this from the Host SQL menu.

UPDATE {databaseOwner}{objectQualifier}DesktopModules SET SupportedFeatures = 0 WHERE SupportedFeatures = -1

Hope it helps,

I've found several post for this problem and all seem to solve it with supportedfeatures fix!

I've the same problem but don't solve with supportedfeatures fix in desktopmodules table. I've several error of this type! My DNN version is 4.5.3

Below you can see one of this error.

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:
Nome server: WIN1804

Nobody can help me with different solution? Thanks!