Are you using a valid lan ip, not 127.0.0.1 ?
Can you ping the one machine from the other?
What port do you have the webapp bound to?
Do you have any Antivirus software that might be blocking it?
You said you disabled the firewall, is that a 3rd party program or windows firewall?
If the above answer is a 3rd party application, did you also open the port in windows firewall?