Steve Stedman fights with collations:
One possible cause of the “Cannot resolve the collation conflict” error message is that your database collation doesn’t match the TempDB Collation.
[…]
Msg 468, Level 16, State 9, Line 11
Cannot resolve the collation conflict between “SQL_Latin1_General_CP437_CI_AS” and “Latin1_General_CI_AS” in the equal to operation.
Read on to see an example of how you can cause this problem and what you can do about it. I agree with Steve’s general advice to keep collations the same across an instance if you can.