Question : ISA outbound Traffic

I've got an isa server 2k4 w/ server 2003 running with 1 network card.  Its only purpose in life is to proxy traffic on port 8080 and authenticate internal users to allow/disallow internet access.  This part is working great.  I have an app on the server itself that needs access to the internet.  However every time i try to go to any site or i try to make this app download its updates (Watchgaurd web-blocker updates) I get the ISA Error Code: 403 Forbidden.  The ISA Server denided the specified Uniform Resource Locator (URL). (122202).  I've chaged system policy rule 17 to allow outbound from the isa server to all networks.  Still no luck?  Any help?

Answer : ISA outbound Traffic

I have to be honest and say this is the recomended approach (different box). The only scenario when the rule changes really is for SBS where SBS uses a modified, cut-down version of ISA server.