Missing groups on Import
Ning To Jamroom
If the NingImport module decides not to import a group for any reason it shows an error message in the modal window. It also puts the error message into the debug log so check there.
The most common reason for not importing an item is that there is no owner profile so check that the missing groups' profiles are imported and were not excluded as 'suspended' or 'left' members.
Were you using the direct media import option? It might be that the missing group images were not available directly from the Ning servers?