I just tried to do a completely vanilla install of 7.3.1. The install script dies out during the creation of the tables, but I can see in MySQLAdmin that the tables are created. I browse to the forum and see the install that failed, but is partially there.

This is the debugging output...

Quote
Generated in 70.079 seconds in which 0.020 seconds were spent on a total of 11 queries. Zlib compression disabled.

So a generic install of UBB is having the SAME result! Dreamhost says that the problem is our scripts...but this is a vanilla install...no customization at all. I had asked Dreamhost to look at it again, but I'm at a loss here. Its like something changed with PHP or something and it is only impacting UBB (an not our other PHP based software, including Photopost).