Problems with load balancing in eB Web

Hi,

We can't load balance two eB Web Servers. We tried many different configuration options for sharing the session state but none works.

This is the error we get:

Exception: System.Web.HttpException
Message: Unable to serialize the session state. In ‘StateServer’ and ‘SQLServer’ mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in ‘Custom’ mode...

Please advice ASAP, thanks a lot,
Sebastian.