502 Proxy Error. The host is unreachable.

I install new ISA 2006 in our remote office. There is a DSL line which i want to use. ISA is configured like edge firewall:
External adapter configuration:
IP 192.168.254.200
MASK:255.255.255.0
Gateway: 192.168.254.254

Internal adapter:
IP: 10.1.17.25
Mask:255.255.255.0
Gateway: 10.1.17.241
DNS: 10.1.17.13

Isa is member of our domain. No body can't access internet. Here is the error from the web browser:
Technical Information (for support personnel)
Error Code: 502 Proxy Error. The host server is unreachable. (10065)
IP Address: 66.45.11.84
Date: 5/21/2009 9:21:05 PM [GMT]
Server: nc-proxy.activescrew.com
Source: proxy

When i look ISA logging tha message there is:failed connection attempt

I did disable ISA and i was able to access internet from the server, so the DSL connection works fine. I can ping the DSL modem also.

Any help please i have be trying to make it work for the last 2 days without success.
Thanks