Cannot access Shared Folder

I cannot seem to allow access to shared folders from a WinXP Pro machine. Here is my configuration:

Peep to Peer "Workgroup"

Computer A. XP Pro
Guest Account: Disabled
Local Security Access Policy | Network Access | Sharing and Security Model: Classic - Local Users
authenticate as themselves.

Computer B. Same setup as Computer A.

Basically, I share a folder in Computer A and allow full access to Everyone

From Computer B, Using a UserName/Password combo that is the same as that on Computer A I can
browse to my list of computers. Upon Clicking Computer A, I see a list of all the shares. Upon
clicking the Share I want access to, I am presented with a login dialog, I try the same
username/password combo, however, the same dialog continues to popup as though I've entered an
invalid username/combo.

incidentally, I can click into shared printers, Scheduled Tasks and a directory under IIS (although
I can't see files here). Recently, I had to so some configuration for doing .NET development for
ASP.NET and I'm wondering if this may have caused problems with allowing other shares.

Any ideas?
- xavier