You add a group prefix in the project options
You then manually map a group to establish a match.
This creates an invalid AD path in NDS Migrator because it appends the prefix anyway.
Log files show cannot bind to group errors and its because the path is incorrect.
This is a known problem and a defect has been logged
The way to get around this is to remove the prefix before you do the manual mappings.
If you have already mapped the objects:
1. Un-Match the object by right-clicking and clicking undo match.
2. Delete mapping.
3. Re-map after the prefix has been removed from the project options.