1st try updating your Java. Use
Java 1.5 (take the JRE)
If it still doesn't work. Post back your modem brand name & model number. Many cable wireless modem use NAT which limits ports of use & particularly limits incoming requests. If yours does use NAT then we can show you how to forward a port (open a port) which will allow LW total access & not just partial acess. Doing so will increase your LW's efficiency & connectivity greatly.