Just came across this little message in a Yellow-Screen-Of-Death of ASP.NET 2.0:
WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLMSoftwareMicrosoftFusion!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 [HKLMSoftwareMicrosoftFusion!EnableLog].
So apparently you need to manually enable the logging of failures to load an assembly. Make sure you do this before you start complaining that fuslogvw.exe (the Fusion Log Viewer, where fusion.dll is the runtime assembly responsible for loading other assemblies) does not work as expected.