I presume you just updated to lw 5?
Make sure both LW's are NOT using the same connection or listening ports. Change the LW on Vista to another port. Can be found via Tools -> Options -> Superduperdadvanced -> Firewalls if using LW 5, else if it's LW 4, Tools > Options > Advanced > Firewalls.
If still problems, post back these details
System details - help us to help you (click on blue link)