ASPX problem

Hey-- this CKfinder program is fantastic! I'm having a problem, though-- I'm able to get it working in a dedicated environment just fine-- IIS 6, ASP.net 2.0. However, when I move it over to a shared hosting environment I get this error:

Server Error in '/' Application.
Security Exception
Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

on this page:
/FCKeditor/ckfinder/core/connector/aspx/connector.aspx?command=Init

Any ideas on what needs to be done? Again, the setup works fine on my dedicated server until I move it over.