Windows – MMC could not create the snap-in

When trying to run the Group policy I get the above message. (MMC could not create the snap-in) Several systems are affected, all WinXP with SP3 and latest updates.

Any ideas on how to get the editor back to working mode ?

I get a CLSID: {8FC0B734-A0E1-11D1-A7D3-0000F87571E3}