You'd be better off not disabling policy.asp as it gives you the forum owner some protection.
To circumvent the firewall problem make the following change to register.asp (I don't advise doing this, but here the info anyway)
Comment out lines 58,59,60 (by placing ' at the front of them), they should look like this
if InStr(Request.ServerVariables("HTTP_REFERER"), "policy.asp") = 0 then
Response.Redirect("policy.asp")
end if