When you submit a new thread to DIYcity right now, you will see a bunch of mysql errors on the submit page.
We've been trying to resolve the issue, but it actually lies with our webhosts - they are timing out the servers too quickly for the full database insert to occur, and this is a host-wide problem.
Just submit your post once.
Regardless of the error message, your post DID go through. You don't need to resubmit.
Will keep trying to fix it, but the only solution seems to be to switch hosting companies.