Reaching backend systems through portal is a problem via dispatcher--

Hi Experts,

I am having problem when I try to reach backend systems through the portal from internet. I have configured WebDispacher according to information taken from help.sap.com, but unfortunately the result is not satisfactory. Reaching Portal EP7.0 from internet is successful, but when I changed to iviews that are referring to backend systems then browser comes to a blank page with error. If any of you having an idea on the subject that will much be appreciated.

Regards,

Ali Taner