For some reason, OpenKM has decided that a document is being "edited by null". The only other post on here about the issue is in Spanish, and even with Google Translate I didn't understand it. How can I resolve this issue?
Even logged in as "admin" I cannot cancel the check-out or anything.
Actually in that thread, the OP didn't get any definite answer either. He said he wasn't able to delete the document as well, even as admin.
Jillort thought it was because the transfer (check-in) was stopped prematurely leading to such problem. He had indeed said that we should enter the repositories to fix it, but personally I think unless you're very good at Jackrabbit, this suggestion doesn't seem very feasible.
I think you should file a bug report. They should implement a "back-door" for admin to delete documents.