One of the very commone things, but hard to solve because most people don't know the answer. I have searched days for an answer and hopefully this answer is the one for you too.
The best solution I found was to re-register the ssosql.dll on the following manner:
1. start the visual studio command prompt
2. go to the ssosql.dll C:\Program Files\Common Files\Enterprise Single Sign-On
3. regasm ssosql.dll
and probably you are finished.