I can access some SMB shares from WinXP, but not all ("The parameter is incorrect")

I have three external USB drives connected to my MacBook Pro running OS X 10.8.3. Two of them are formatted as Mac OS Extended (Journaled), and I can access SMB shares on them from my WinXP computer. One is formatted as MS-DOS (FAT32), and I cannot access shares on it from WinXP. I can see the volume from WinXP, but when I try to access folders on it I get an error saying "\\<volume>\<share> is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. The parameter is incorrect."

I formatted the drive for FAT32 in WinXP using Seagate's DiscWizard utility due to the size of the drive (1 TB) so that I can access the drive when I plug it in directly via USB into either computer.

My username and password is the same on both the Mac and WinXP computers. I have also tried enabling the Guest account on the Mac (sharing only) to no effect.

On the Mac, I have tried explicitly sharing the folder I'm trying to access (as well as the entire volume), but I get the same result. In System Preferences / Sharing / File Sharing, I have Windows File Sharing turned on, and in Options I have SMB enabled. My local user account is also checked under Account. The folder I'm trying to access is listed in Shared Folders, and my user account (and Everyone) is listed as having Read & Write access.

Besides FAT32, the only difference I can see in Finder between the two drives I can access and the one I can't is that when I view "Get Info" on each of the drives, the FAT32 drive says only "You can read and write" under Sharing & Permissions, whereas the other two drives that I can access actually list my user account with Read & Write, Staff (with Read & Write), and Everyone (Read Only). In System Preferences / Sharing / File Sharing where the share is listed, my user account (and Everyone) is listed with Read & Write access, but the permissions are greyed out, and so is the '+' symbol to add additional users.

What am I missing?