Windows 7 - Can't connect my W7 32 bit laptops to shared printer on Vista 64 bit

I think I've enabled all the necessary sharing permissions on the host, Vista 64 bit machine.

The host Vista 64 bit machine is not mine, I'm not permitted to change it to Windows 7, it is there to stay.

With Printer Sharing turned on (Vista 64 bit) and the computer as "discoverable" on the network, I am unable to connect to the Vista 64 machine at all with any of the three Windows 7 laptops in the house. I have a MacBook Pro also, which does see the Vista 64 machine on the network by its correct name. I'm not able to connect to it from the MacBook Pro, but that's another issue and not something I want to deal with right now. I just need to share this printer that is connected to the Vista 64 machine amongst three or four Windows 7 32 bit laptops.

Is there some special issue getting the Windows 7 machines to talk to the Vista 64?

I tried various ways of addressing the Vista 64 machine, including "\\machine-name" and "\\machine-name\printername" and I'm just getting radio silence from the Vista 64 machine.

Everyone is connected to a verizon fios router. Everyone has internet access. I see all of the machines when I browse the network using my MacBook Pro.

Can anyone help me get these Windows 7 32 bit laptops able to share that Vista 64's shared printer?