Unable to share XP Home folders... help

[Bruno]

I need some help!

I have a home network setup as follows:

a. Network (shared through a D-Link-614+ Router)
#1 P4 XP Home SP1 (Desktop)
#2 PIII XP Home SP1 (Desktop)
#3 PIII XP Pro SP1 (Laptop)
#4 P266MMX Win'98SE (Laptop)
All computers are running software firewalls (Sygate) that are
configured properly.

b. Computers 1 and 2 are connected through the 100BaseT LAN.
Laptops 3 and 4 access through the Wireless 802.11b port.

c. All computers are in the same workgroup.

d. What's working...
Computers 2,3 and 4 can access each other and see the shared
folders.
Computer 1 can access all of the other's shared folders.

e. What's not working...
Computers 2,3 and 4 can see computer #1 but they >>CANNOT<< access
the shared folders of computer #1. The message I receive is:
"Access Denied"

f. What I have done...
- I have disabled all firewalls.
- I have disabled the hardware firewall in the router.
- I have swapped the computers ports on the router.
- I have created new users and new connections, then shared them
via a floppy diskette.
- I have tried another router (Linksys, wired).
- I have flushed and rebuilt the IP stack of #1.
- I have searched MS' Resource Center and elsewhere... no joy.

I am at a loss and I now wonder if the only way for me to get out
of this predicament is by upgrading to XP Pro (?)

Thus, I turn to this group (and others) to point me towards
something I might have missed.

Comments? Help?

Thanks in advance ;-)

--
Bruno,
Oceanside, California