Thanks, Jason, that seems to have corrected that issue. Everything is working fine now in 'Live' mode, but when I change the mode to 'Test' in the PayPal Manager Set Up screen and run a sandbox test I get the following error when I dump the POST variables:
["RESPMSG"]=> string(42) "Field format error: Secure Token Not found"
even though the secure token can be seen further down in the dump:
["SECURETOKEN"]=> string(25) "SPBN5KjdDzUyByZ65VIXcgwR8" ["SECURETOKENID"]=> string(32) "4723e02fe457cbeae48f7eb073e3a5e3"
Could this be related to the problem you found earlier in the confirm.php file?