ASPX missingfieldexception error

I have just updated 开发者_开发百科my company website and it looked fine at first. Then a few seconds after loading, I encounter this error:

System.MissingFieldException: Field not found: xxx.include.NaviBar.ASPnetMenu1.

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Couple questions:
1.) Are you on a shared server that is perhaps running in a Medium Trust environment
2.) Is this a custom site or a framework, like dotnetnuke?

The missingfieldexception usually comes up when you're using reflection and are trying to access a property or method that doesn't exist. Medium Trust environments sometimes won't allow the reflection classes to be called, or the access to the functionality is limited.

http://msdn.microsoft.com/en-us/library/system.missingfieldexception.aspx