Thank You and Check out page is missing

[lindafan]

The page of thank you and checkout page is missing after I clicked "Confirm".

The message is 500, no valid database connection.

This is the 2nd times occurred this problem.

In 1st time, I need to reinstall the Joomla.

But how to solve it? And why is disappear?

My website is www.australianfinewine.hk

[PRO]

what version are you using? THIS IS the 1.5 forum, 1.5 is NOT finished