*slaps himself*
OK now I feel stupid!
But I followed the rest of the steps, and for some reason, I'm now getting a forum database error... imported the product and made the two index.php changes, and now I'm getting a database error page.
FYI, I ran a query earlier today for another gallery mod:
https://vborg.vbsupport.ru/showthread.php?t=92875
Would this have anything to do with this error?