isa server 2006 standard edition

Hi
I installed isa 2006 standard edition with 2 NICs,,when i created the rule that allow all outbound traffic from internal network to external(internet),,i’ve faced this msg as shown blow,,
Technical Information (for support personnel)
Error Code 12206: Proxy chain loop
Background: The gateway has detected a proxy chain loop. This condition might indicate a configuration problem on a proxy server.
Date: 12/2/2010 1:24:03 PM [GMT]
Server: isa
Source: Proxy
I look forward to hearing from you and thanks in advance