Open /include/class.ticket.php and locate line 1010 there are 2 errors on that line
The word vacation is misspelled as 'vavaion', and toward the end of the line the part that reads '$dept->getDeptId' should read '$dept->getId'
Correct those 2 issues and the emails will begin to be deleted once they are added to the tickets database by the autocron.
On another note:
I am also experiencing a problem which I have had no luck tracking down where the cron job does not retrieve the emailed tickets. I have added it to my crontab to run every 15 minutes, but when I manually run it from the command line, nothing happens and I am instantly returned to the command prompt. I've looked through the forums here and then the source code and not been able to find the cause. Anyone having similar issues, or am I overlooking something obvious?