PTC Creo Schematics 2.0 is not registered with the Workgroup Manager

For me Creo Schematics 2.0 was working jsut fine with work group mangaer. Now when i tried to open an .rsd file, WGM now says "PTC Creo Schematics 2.0 is not registered with the Workgroup Manager" . I tried to delete Creo schematics from Application management and re-register again. But It seems I can't delete also. Error message is attached here.

Can anyone help? It is a complete work stopper for me.