@coderus:

I cannot reproduce it anymore - I did "Unapply all patches" and after that, the patch applied successfully. For some reason it did not get loaded on the first try (ie. the patch was applied, but there were no changes in the UI), but on the second attempt everything was restarted, and the patch loaded.

Judging by the logs, I think the initial failures were because PatchManagerObject::doPrepareCache did not create any files in /tmp/patchmanager, although I have no idea why.

If you think it would be useful to you, I can send you logs from when the patch was applied but not loaded. I don't have logs from when the patch failed to apply; I can try to reproduce it later by uninstalling PM and the patches, and starting from scratch.