I wonder if the initial 6.4 altertable query did not fail for you - then mine just redoes that query - but some of the fields already existed, so the query failed.
In other words - it puzzled me that the altertable failed, although it doesn't on all servers. My Field was U_BirthDay - the new field is U_Birthday but on a Linux server, it says the field already exists. Not sure if different setups might not have had a problem with it.
