Hi WierdAl,
Sorry, but I'm not sure exactly what problem you're having. Are you having a connection problem? If not then please let us know what your problem is. I'll assume it's a connection problem for now.
The latest Java update should be fine:
Java Downloads for All Operating Systems - Sun Microsystems
Download the Windows offline installer. After downloading the installer, remove any other Java versions installed via Add/Remove Programs. Install the latest Java & then reboot your computer.
Check your router's manual to see whether it supports UPnP. If so then you'll need to log into your router & check to see whether UPnP is enabled (see the router's manual for details). Once UPnP's enabled within router config, go to LW's tools > options > advanced > super really advanced > firewall. Make sure that the button to use UPnP is checked. Click ok to save any changes.
This thread has other fixes for connection problems:
If LW 5 Will Not Connect
If you're still stuck & need help with port forwarding, let us know
And for info about how to start a new thread, check out the link here:
How to create a New Thread; Your First post .. how to start it