Mine is different
the line look at the change I made mine says 287 yours says 285
Now you can not use PhotoPost Integration if you do not have photopost installed. There is a photopost selection on the external registration which is for users who have photopost. If your wanting to do a standalone you select internal registration on step 3.
Right in the sellerspost.php file in forums subdirectory there is a function called get_regcode
Content visible to verified customers only.
If you have that regcode error check your classifieds database what is the value of setting 41 in the settings table?