VDS import to new vCenter fails

In the process of migrating to a new 5.1 vCenter we upgraded our old vCenter from 5.0 U1 to 5.1 since we rely heavily on vds. This would make it possible to export current VDS configurations and import them to our new vCenter. When I try to import the VDS Configuration to the new vCenter I recieve this error :

Any help would be greatly appreciated..