Unable to generate a temporary class

If you are running your Proxy service and are trying to load the proxy assembly and get this error you are seeing a permissions problem. Basically .NET is trying to create a dynamic serialization assembly at runtime and is failing because it can't access the output folder.

Typically the folder in question, is the System level (not user level) temporary folder, which usually points to:

c:\windows\temp

but you should check your System Environment settings.

In order to fix this issue you need to make sure that whatever account(s) or group(s) are trying to run the service have rights to read/write in this folder.