Class 'udperms' not found - but why?

I’m puzzled at at this, it’s actually happening on a couple of installs one of which is 1.0.3 but as most are 1.0.4 and I’m planning to move the test one to match...

PHP Fatal error: Class ’udperms’ not found in /home/managed/terminal/www/manager/actions/mutate_content.dynamic.php on line 67

Okay, nice and simple but... /home/managed/terminal/www/manager/processors/user_documents_permissions.class.php exists and is readable by the server. I’ve changed the include_once to require_once and no error unless I rename the file. So the file is there and being read, but the class isn’t being found.

Any thoughts or tips greatly welcomed, I’m going round in circles here - I’ve even re-downloaded and uploaded half a dozen times now...

Env: ModX 1.0.4 FreeBSD 7.3, PHP 5.3.3 with Suhosin-Patch, mySQL (server and client) 5.0.90, pdo_mysql installed, pecl-APC-3.1.4 installed

Try disabling APC and see if it still happens.

And the simple answer is, no - disabling APC did fix it...

Now to see if I can figure out a way to have my cake and eat it

Cheers for the pointer.