WSUS Version mismatch 3.2.x 3.2.y ?

What does this error mean, if i try to publish 3rd Party updates to another wsus-server?:

"The Server has the required certificates for Publishing. There is a version mismatch between the WSUS Server API version: 3.2.7600.274 and the WSUS Client API version: 3.2.7600.226"

I have 3 WSUS. 2 of them (one of them PM) are Server 2008 R2 and are showing Client and Server api version 3.2.7600.274. The 3rd with the Error is a Server 2003 R2. The WSUS console on the 2003r2 Shows version 3.2.7600.274 for this Server, but in the programs/software list (programs and Features in Server 2008 r2) the KB2720211 is listed as removed (and this isn't removable).

1. I thought a mismatch could only occur between main Versions like WSUS3 / WSUS6 and so on?

2. How can I update the Client API on WSUS? Do it have to selfupdate? And how can I force this with Patchmanager?

Thanks