File Sharing Issues - Can't Get My Home Network Running

I'm attempting to create a small home network b/w (2) computers. Although I
can see all shared files within the network, I cannot access the files.
Specifically, when on computer B I can see the available shared folders
within the workgroup on Computer A, but when trying to access I get the
following error:

" .... 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. Access denied."

Here's the set-up:

Computer A:
* Windows XP Pro
* Network wizard was run and a disk was created then copied to Computer B
* For all files that I intend to share with Computer B, I went into
properties and set-up security to allow file sharing with FULL control.
* NetBIOS over TCP/IP has been enabled
* System Mechanic Pro 9 installed, but using the Windows firewall.
* Windows firewall enabled but File and Printer Sharing is permitted.
* RestrictAnonymous set to 0 in the registry
HKLM\SYSTEM\CurrentControlSet\Control\LSA
* Service Patch 3

Computer B:
* Same as Computer A EXCEPT I have not installed Service Patch 3; Computer B
is operating on Service Patch 2.

From a network standpoint, I'm using a Linksys WRT54G, in wire line mode
only. The firewall for this router is enabled.

From all of the info I've read it would seem that the only think I haven't
tried is to physically move the folders I want to share to the Shared folder,
instead of just changing the properties of each individual folder to allow
for sharing. My concern being that by moving the folders to the Shared
folder they would no longer appear in My Documents. I'm not sure how that
would work.

Anyway, lots of information. Hopefully it's enough for someone to help me
get my network off the ground!

Thanks in advance for the assistance.

Regards,

mucrick