Well, I believe I have solved it! I'm assuming we have the same issue...
The paths is not the issue...except for some reason using the variable name $folder. (is that a reserved word)? Anyway, it doesn't work for mine, and I had to change it to $base_folder so that it wouldn't get messed up and not call the other two require_once lines below library in ipn.php.
The other problem is actually really easy to fix, but a pain in the ass to find! :-) It's a typo of sorts... In ipn.php the switch statement is making use of $paypal["post_method"] and $paypal["url"] in each of the conditions. These variables old carry overs from Form Tools 1 (or maybe they were supposed to somehow be included in the $paypal array that is the result of the array_merge at the top of paypal_submit.php. Either way it doesn't get carried over to ipn.php)...but since Form Tools 2, these variables have moved from config.inc.php to the includes/library.php folder. They also got renamed:
$pp["url"] and $pp["post_method"].
The paths is not the issue...except for some reason using the variable name $folder. (is that a reserved word)? Anyway, it doesn't work for mine, and I had to change it to $base_folder so that it wouldn't get messed up and not call the other two require_once lines below library in ipn.php.
The other problem is actually really easy to fix, but a pain in the ass to find! :-) It's a typo of sorts... In ipn.php the switch statement is making use of $paypal["post_method"] and $paypal["url"] in each of the conditions. These variables old carry overs from Form Tools 1 (or maybe they were supposed to somehow be included in the $paypal array that is the result of the array_merge at the top of paypal_submit.php. Either way it doesn't get carried over to ipn.php)...but since Form Tools 2, these variables have moved from config.inc.php to the includes/library.php folder. They also got renamed:
$pp["url"] and $pp["post_method"].