I'm going to piggy-back this topic, because it's what I have issues with as well, but mine are more technical questions now...
Problem: SELECT command denied to user
Info: The cause of this error is that SMF and Software X are in separate databases and the SMF database user does not have access to Software X's database.
Fix: If your host has cPanel you can add the SMF database user to Software X's database. If your host does not have cPanel you can contact them with regards on how to accomplish this. As well as a last resort, what you can do is reinstall SMF in the same database as Software X.
My hosting doesn't have cPanel.
My hosting also says that they cannot add a second user to a database.
So - do I manually download SMF and install it into the phpbb3 folder of my choice, and then run the conversion program from there?
Would that be the best option, or does someone know how to add a user to a database through myphpadmin & SQL?