From what I can ascertain New Modems from OPEN Networks; any good? - Westnet (down to at least half way down page) it may be a firmware issue (though that is an oldish article). My guess is it still does have issues.

Make sure all the LW's that run thru that device use different ports. That may also mean changing your McAffee firewall settings. For LW, Tools>Options>Advanced>Firewalls. Also, Tools>Options>Performance & disable Ultrapeer capabilities on all LWs. Chances you won't be able to become one anyway with firewall detection.

On your iconnectaccess 624 make sure UPnP is enabled. Tell us if UPnP was not enabled on it. You will need to log into the device to check.