A nifty utility for troubleshooting .NET assembly load errors is FUSLOGVW.EXE.  It can be found in the .NET SDK\bin directory.  It is a bit finicky, though.  The 'view log', and 'delete' buttons apply to the current selection.  You can only select a row by clicking in the leftmost column.

Normally, only failures are logged (provided the 'log failures' checkbox is checked).  However, a couple of registry settings will control what else is logged:

• HKLM\Software\Microsoft\Fusion\ForceLog = (dword)1 logs all binds
• HKLM\Software\Microsoft\Fusion\LogResourceBinds = (dword)1 logs failures to satellite assemblies