MigrationTool can't find prefix

Hello.

I have looked all over the place, but can't find information to help me with this prob.

I want to convert my PhpBB forum to PunBB.

But the migration tool can't the tables for phpbb in the database.

I'm not sure, but the cause can be that i sort of "integrated" PhpBB with Mambo. The installation of PhpBB is "free" in an own directory and has its own tables in the db. Could that be the cause of this problem?

Thanks for any help at all!