I’ve not had that error, but after a little Googling I came across this link, I’m not sure if you’ve seen it yet: http://forums.asp.net/t/956297.aspx
Edit (adding the key text):
This error will come when a reference is specified in web.config and deployment folder/site does not contain these dlls installed in the system or bin folder does not contain them(if they are private assemblies).
For Example: (add assembly=”Namespace1.NameSpace2, Version=x.x.x.x, Culture=neutral, PublicKeyToken=31bf3856ad364e35″/)
if your web.config contains any assemblies like this and deployed server doesnot contain these assembiles in bin or GAC, then this error will occur.
People were reporting that missing assemblies on the destination server ended up being the root cause, in their cases, but they had the same error as you. Weird.
Maybe that’s the problem?