While doing an automatic upgrade from 1.2.1 to 1.3 I encountered an error telling me that I was running PHP4, not PHP5. (This was actually true because my hosting provider is messing around whith my account currently.) So I corrected that in my php.ini, but now I'm getting an uggly DBQueryError telling me:
Query failed with message 'Unknown column 'default_billing_id' in 'field list''
Help please!
P.S. We should absolutely check the PHP version again before running the upgrading procedure!