Hello looks to me like you have altered your vb3 default profile structure in your vb3 admin
We look for the user location field in the userfield table field2. If you have changed/deleted profile options you may need to update our vb3.php file and correctly alter the query to the user field location is stored at. We code queries based on default installations.
Okay and thats your issue as in a normal VB3 there is a field called field2 which holds the user location.
You need to do one of two things. Either add a field2 back into that database table so you will not get an error anymore or alter the query in our file to point to a database field that has the user location. I think just adding a field2 back into the table would be easiest for ya through phpmyadmin
I added the field to the table, then posted a couple test comments. I don't see any error code now, so it seems to have worked. I'll ask a few users to test it, too.