Oscommerce express checkout is not working

i have oscommerce 2.2 with many mods...one mod is making me problems with wpp 9. it is the easy checkout mod, when i use the direct payment it's working perfectly but when i click the "checkout with paypal" (paypal express checkout)' i first get redirected to the paypal website to login which is good, then when i hit "review payment" paypal send me back to "checkout_shipping.php" and there i see: QUOTE: "You're currently checking out with PayPal Express Checkout! Click Here to choose another payment method. Continue Checkout Procedure to select the preferred payment method. " then when i hit "Continue Checkout Procedure", it takes me to the same page with the same message...nothing really happens [login to view URL] Shouldn't i get transfered to [login to view URL] when paypal redirect me to review the payment? whet on earth can cause this problem? btw, i tried reverting the "easy checkout contrib" to use the actual files from wpp 9 and the express checkout worked but other thing didn't... I need someone with experience that already hendle both easycheckout mod and WPP.