Well there are a couple of free mysql hosting servers out there (incase you didn't know), and also converting all that stuff can be done by some forums... like Invision Board, or phpBB.
Let me check:
* Checking.....................
.......
* Confirming...................
.......
* Going to toilet.......................
...
Done!
Ok, so this is what i got. Invision Board does not convert from UBB. However, phpBB does!
Even found a howto post on the phpBB web-site on howto convert UBB 5.x into phpBB 2.x
http://phpbb.com/phpBB/viewtopic.php?t=70989&highlight=ubb+5+45b I hope you convert, and I also hope I helped =)
Also, phpBB 2.x could just be the middleman. I know alot of forums that's got a phpBB2ThatForum converters.