OSx Refuses to network (1) of my (3) WinXP Machines ?!?! - Sharing and Printing

Hello all, I am new here.
I have a burning question about networking this ONE WinXP PC I have...

Actual Problem:
I have a network, 3 XP Machines and one iMAC OSX 10.3.9

From the IMAC, I "can" connect to 2 XP Machines and their printers. The 3rd machine SHOWS UP in the network and printer list on OSX, but the network says "Item could not be found" and the printer says "Cannot use the username and password provided, error 256", no matter what username I use.




Additional Information:
I "assume" I have all the password CORRECTLY set up, because, I can see and print FROM any terminal TO any terminal, EXEPT I cannot see the 3rd PC FROM the iMac. I "can" see the imac from this pc, though.

I can ping the PC from the imac, I can also ping the imac from the pc -- The network Seems OK except its' not apparently ...

All the computers are on the same router, same netmask, same workgroup. They all have the same user-names and the same passwords. They have been restarted many times.



What I want to do:
All I want to do is connect the two shared printers on the 3rd XP machine to my iMAC so I can print !


Conclusion:
The iMAC simply refuses to connect to the 3rd XP machine, even though it SEEs it in the list, and the password IS valid.

ANY IDEAS ??

UPDATE

I still have absolutely no idea what is causing this, but I found a way "AROUND" this, for printing, for any one in the future searching with the same problem.


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You can enable Windows IP Printing and create an IP Printer, then you can add an IP Printer to OSX and print over the network, without having to use Microsft File / Print sharing.

I found a quick reference page basically guides, here:
http://homepage.mac.com/corrp/macsupt/macosx/printing/sharedwinprinter.html



What you do:
Open Add/Remove programs in XP,
Click Windows Components,
Scroll down, click Additional Network / Printer
Select IP Printing For Unix
OK
Insert your CD and install it....


Now From the iMAC, ADD a new printer,
Select IP Printer, (IDL Or something like that)
Enter the IP address of XP machine,
Enter the share name of the xp printer in the 'queue' selection
Add the printer

PRINT !!!

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Thanks for any help, I still hope to resolve the original problem, but I hope this can help anyone else with this problem.

Thanks all!