Wow. Now I am going to be doing a little "shooting in the dark" then...
First, I would "refresh" the DNN assemblies by grabbing them from a fresh download of the version that you have installed. So, if your site is running v4.06.02, be sure to download that version. Then, grab all of the assemblies in the BIN folder of the freshly downloaded install, and drop them into your BIN folder.
Recycle the application to make sure that the cached assemblies are removed from memory.
If that doesn't work, run a query to make sure that all of your modules that have the SupportedFeatures flag set to 0 and not -1. Once again, recycle the app to refresh the cache afterwards.
IN SQL SERVER MANAGEMENT STUDIO
UPDATE [dbo].[DesktopModules] SET [SupportedFeatures] = 0 WHERE [SupportedFeatures] = -1
IN HOST MENU > SQL PAGE
UPDATE {DatabaseOwner}{ObjectQualifier}DesktopModules SET [SupportedFeatures] = 0 WHERE [SupportedFeatures] = -1