we have a problem with our paypal ipn callbacks on a subscription setup we have. when the sale comes in all works fine but when the reoccurring ipn call comes in the [url removed, login to view] is dying before it can do all the processing. this is all done on a heavily modified oscommerce type site.
you need to know oscommerce ipn and paypal to be able to fix this.
i know its something stupid we are missing.