NAV and CRM Authorization Error

Hi,
I was working with NAV and CRM Integration, for this purpose i had develop a dll that is called by the NAV application to fetch the data from the CRM. This method is working perfectly great as i required. The NAV and CRM are installed on Sandbox.
Now i have also Install the NAV RTC in my local computer and configured it. Now the problem is when i run the Integration job it does not work and break with the error:

failed with the following message: The request for authorization of type System.Security.Permissions.SecurityPermission, mscorlib, Version=4.0.0.0, Culture=neutral,