[rnln]

Not exactly the 500 error problem, but I encoutered similar problems with several work places. I am not sure if my little experience can help but maybe a reference. Once it was dish space available. We were using SQL server and had only 2 or 3 G left. Rebooting server would fix it for 1 or 2 days. Another time was the same cause, disk space, but it behaved as application problem. Watching the numbers of loging in, it kept increasing and won't decrease after users logged out (leaving the dead process behind). It acted as you forgot to close the connection to your DB in your application. Temp fix for us was running a connection kill at night, and made sure to include the log file when you do your backup. This log file can get pretty big if you allow. Anyway, after we upgrade disk space, problem was gone.

Yes, tonight I don't see the usual slowliness problem.

Also, there is another problem related that I forgot to mention. That is the data is not saved. User would think it's saved since it acted normal. And I think you might have the same problem, since there were several replies I posted but never see it again.