Question about Belkin Pre-N router setup

Hello, I have a Belkin F5D8230-4 that I'm trying to replace my old
802.11b router with.

I run several web servers on one of my local LAN machines, giving it a
static IP on the local LAN.

Because my ISP blocks port 80, the sites run on specialized port
numbers - in the 8000's. I use the "virtual server" option on my
existing router to pass the desired ports to the server box. Also,
I'm using a dynamic DNS service to keep my ISP-assigned IP mapped to
my domain name.

With all this running, I tried to replace the old router with the
Belkin. The wireless and the basic routing seemed to work fine, and I
used the Belkin's port-mapping config page to reconfig the port
forwarding I had set up in the old router.

I have been unable to access any of the web sites I have forwarded.
When I look at the Belkin's log, I see entries mentioning blocked
accesses due to DoS protection. I went the Belkin's firewall config
page and disabled its firewall - I still cannot access my web sites
and I still get the "DoS protection" entries in the log.

Have I missed something?

Thanks for any help/advice.