The Application Data folder's hidden by default, so you'll have to show hidden files & folders to be able to see it. Go to Control Panel > Folder Options > view > check the radio button to show hidden files & folders > apply > ok.

Now it should show up Don't forget to look for a prefs folder in the old location (C:\Documents and Settings\your username\.limewire), if you've used much older versions of LW before.

Try port forwarding for your speedstream, the instructions are here.
Port Forwarding for the Siemens 4100
Don't forget to set up a static IP address first, otherwise port forwarding won't work. LW's listening port, port in the 'manual port forward' box & port forwarded within the Speedstream should all be the same number.