weird fatal errors… wp just stopped working

I contacted my host, because I am guessing it’s a problem from their end, but wondered if anyone had thoughts over here.

Sometime within the past couple of days, my websites went down due to php errors. But I didn’t change anything. In other words, everything worked fine last time I logged into them, but today they are dead. Non-wordpress stuff on my server seems ok. Just wordpress has broken and just brings up dreaded php error messages.

Looking at the error messages, I ftp’d and found the files referred to; comparing to a recent backup it seems like possibly the php files became truncated? Corrupted? Weird. The files on their server are not timestamped to indicate they have changed or anything.

I am wondering if I should try reinstalling, or replacing the dubious php files, or what. The mysql databases look ok as far as I can tell. I am waiting to see if I hear back from the host. But are there any other likely things that would cause this? Some rogue plugin? Something about the php version? I am pretty savvy but no expert on these things.

Also this happened to two different wp installs on the same host so it seems like this must be a problem from the hosting end… either the files got corrupted or there is something wrong with the php version.

Any thoughts?