Hi,
I think the problem is due to non UTF8 chars in alias of field groups, to fix try this:
- upgrade to version 1.1.12 (to have improved batch feature)
- Create new fieldgroups with UTF8 alias
- Move fields from old fieldgroup to new (you can use batch to move many fields in one step)
In latest release we have added a function to remove non UTF8 chars to avoid this problem.