500 - internal server error after email backup restore

Hello,

I'm facing a very strange error...2 days ago I restored only the emails for one account (extracted the backup .tar, uploaded the contents of the cur folder to the according cur folder on the server, changed the permissions to 660 and set the ownership to the according user).

Since then, everyday after (or during? haven't figured that out exactly) the daily backup process I get 500 error on every site hosted on the server, which stays like that until I restart the server. Nothing special on the apache error_log except some 404 errors, and no errors in suphp_log either.

Another strange thing: When I use the "Repair mailbox permissions" from whm I get the error:
[a fatal error or timeout occurred while processing this directive]file error - cache failed to write mailperm.tmpl: Not a GLOB reference at /usr/local/cpanel/Cpanel/Template.pm line 122

And of course after that the 500 error everywhere until I restart.

I tried deleting completely the specific mail account that I restored from the backup, but the problem remains.

Any good ideas?