Bug with Pun_pm on punbb

Hello,

I have a problem with the extension "Pun_pm" on this site.
When I wanted to delete all my outbox messages, I was redirected on the same page, but some were not removed PM.

I now have this:

I can no longer possible to check messages.
When I click "Select All", I get this message appears:
Annouce of page  http://punbb.informer.com  : No message is selected. You have to select messages to delete.

This problem is only in the Outbox.

Regards.