If you attempt to use the SilverLight Toolkit on the Windows Phone 7, you might get the error “Could not load file or assembly". Apparently the issue arises from a bug with running dlls signed with certs other than Windows Phone certs.
For now the only way to continue building apps is to remove the certs on these dlls.
Instructions for doing this can be found at: http://bit.ly/aODiLV
Note: you might have to run the following command before attempting to run the script on that site:
(the command set-executionpolicy remoteSigned, did not work for me). Also, remember to start your command prompt in Admin mode on Windows 7.