The “right” path to use on line 4 of Paypal.php is somewhat ambiguous, so I might have gotten it wrong (though it works on the servers I tested it on.) There are at least 3-4 possibly correct paths that I can think of.
Here are some possible variations on that line, in order of best to worst. Could you try these and tell me which, if any, work for you?
require_once BP . DS . ‘app/code/core/Mage/Paypal/Model/Standard.php’;
Once I get your feedback I’ll push out another update with the best fix.