I am still trying to figure out why, I have tried a few different things but to no avail, I even tried with the goal amount set to $1200 and it did not work (but I knew it would not, I just did it for sanity's sake) I am really starting to believe the server is blocking the info from coming back.
The auto confirming is completely dependent on PayPal's servers notifying *your* server of the transaction. If PayPal's servers are backlogged, then your store will NOT see the order until PayPal's servers catch up, also if PayPal is not able to reach your server for some reason. Have you made any changes on the server in the past few days, maybe the firewall or something is blocking it?
Can you look at your server's access logs and see if it is actually trying to access your site, should look something like this, 173.0.81.1 - - [28/Aug/2012:21:29:57 +0100] "POST /vbdonate_gateway.php HTTP/1.0" 200 - "-" "-", and then check your sites error log and see if you see something like this, [Tue Aug 28 21:29:57 2012] [error] [client 173.0.81.1] client denied by server configuration:
I will continue to dig into it.