I am running a Moodle 1.9.9+ (Build: 20101020) server on a Windows 2008 box with a MS-SQL server on a second box to perform the back-end chores. My version.php file lists the Certificate Module Version as 2009080900. My version of PHP is 5.2.14.
On occasion, one of my users will attempt to generate a certificate. Most of the time this works cleanly, but in a few of the cases, at attempt to generate a certificate creates a Server HTTP Error 500.0 Internal Server Error. At this point, ANY user who goes to the Certificate module gets this error. If I re-start web services on the hosting server, the problem goes away, but not for good.
This is proving hard for me to isolate, because it is not persistant. Has anyone else seen this behavior?