If you are ok running without AV scanning, you should be able to disable the scanner and then get zimbra started successfully. From there, based on the fact you are running version 5.0.14, I'd suggest grabbing a fresh backup and then upgrading to current version as this will likely solve your problem.
EDIT: It's likely that this is all linked to this:
ClamAV 0.94 EOL on ZCS 5.0.16 prior (discussion) but I wouldnt have thought the resulting problem would be a segfault.