GWCheck: deldupfolders did not resolve problems

Hi Forum,

we run every weekend content gwchecks on all post offices.
One User is suspicious with entries like:
- checking Folder records
Problem 79- Folder Primärbuch (record 53959) duplicates folder 53958 at the same level
- Renaming folder to Primärbuch.dup1
- Record 53959 updated successfully

This goes on until Primärbuch.dup1456
After multiple gwchecks with misc option "DELDUPFOLDERS" only up to "Primärbuch.dup483" are left.
But I can't get them deleted/fixed.
One Error in the log file is:
Return from WpPabRemoveDuplicateBooks = 0xE71E

Could this be the cause why the other 483 duplicated primary books are still there? Unfortunately I can't find anything about this error code... how can I fix this?

Thanks in advance,