ComErrorException 'Class Not Registered'

I'm trying to write a integration(unit) test that calls an object from SQLServer Replication dll.

When it tries to instanciate the object MergeSynchronizationAgent i get an exception:

'{Class Not Registered}'
-2147221164

I tried switching the platform to x86 but that didn't work.

The exact dll is Microsoft.SQLServer.Replication.dll.

Any help is greatly appreciated!