Dear Jelo,
We usually receive this error when we try to change the Standard Hierarchy thru KSH2, note below the SAP procedures for that:
Group XXXX is not unique
Message no. OH072
Diagnosis
You wish to process group XXXX, which is not unique.
A group is unique if it only contains each subgroup and each value once. Value intervals may not overlap each other.
System Response
The system only allows the display of ambiguous groups (not maintenance).
Procedure
Re-create group XXXX as unique, or restrict processing to unique subgroups within group XXXX.
To remove ambiguity, proceed as follows:
Choose Extras -> Ambiguity check. The system displays all of the groups and values which occur more than once, and all overlapping values.
Remove these groups, values, and overlapping values by processing the affected groups directly.
If the standard hierarchy is affected, the compare function enables you to compare the master data (Extras menu).
Once all the ambiguities are removed, it is possible to process group XXXX again.
I hope this helps you.
Best regards,
Gabriel Coleti