I'm running PHP 5/MySQL/Apache 2.2 on a Windows Server 2003 box (sorry) with open-source content-management software. About half the times when one of our content managers uploads a document (could be as small as 8kb), Apache stops. I check the Apache error logs and every time this happens I get an error that reads something like this:

[apc-error]apc_fnctn_unlock failed errno: 6

APC is the PHP accelerator we're using. Does anyone know what is causing this or anything to try? I set the APC memory limit 64MB (default is 30) and Apache still stopped. I also tried turning off apc.stat, but that took down Apache, too.

The server has 2GB of RAM. I really need to get this fixed. Any ideas would be appreciated. Thanks.

Sorry but I don't know anything about apc, however a quick check on their web site prompt a few questions, of which the answer may already be yes...

1) Installation
To quote the manual...
"On Windows, APC needs a temp path to exist, and be writable by the web server. It checks TMP, TEMP, USERPROFILE environment variables in that order and finally tries the WINDOWS directory if none of those are set."
2) Configuration
have you set apc.write_lock to true?

I looked a bit at the documentation. apc.write_lock is set to "1" by default. So that should be fine. I still need to check the temp directory and other settings for apc in the php.ini file. Do you know of a good PHP forum out there where I could ask about APC?

Ok, I fixed the problem. Apparently, both Zend and APC don't work so well together so I commented out the "extension=php_apc.dll" line in the PHP.INI file and the problem went away.