Bizdude Win XP has its own firewall. Did you disable it or not do anything. See
Firewall configuration instructions (click on link)
I didn't notice any mention of UPnP capability for your
Aztech DSL305EU which means you might require port forwarding. Particularly if you use it in ethernet mode.
There's 3 steps to port forwarding. And the setting up of a static ip is the 1st you must do & must do properly for this to work at all!
The steps:
1. Set up a Static ip
2. Forward
port 6346 following these instructions:
Guides for the Aztech DSL305EU (also includes instructions for setting up your static ip!
3. Within LW:
Manual port forward instructions & sample image & 2 posts after that.