Help with "Parse Error, no assembly associated with Xml key"

[snow]

Hi,
First of all, I'm using .NET remoting Framework 2.0 and I can not upgrade to a newer technology.
Here is my problem:
I'm getting the following error "Parse Error, no assembly associated with Xml key .." in the following situation:
1º - run application X
2º - create proxy A to remote object A and call method from A; - OK
3º - set callContext on object A; - OK
4º - create proxy B to a different remote object B in different IIS virtual paths and ports; - OK
5º - call method from A; - here is where I'm getting this exception.

For some reason the proxy B is trying to deserialize the 'callContext' class from the object A.

This is not making any sense!! Anyone else had this problem?
I appreciate your help!

I'm doing this through interfaces, so each web service as a different interface and implementation.

Regards!