WinXP wireless problems in ad-hoc mode

I have a desktop and notebook that I want to share file between them
and for the notebook to use the printer which is connected to the
desktop. Both are running Windows XP Home edition SP1, running Avast
Antivirus. Both have Zone Alarm installed for internet firewall, but,
the desktop is the one only running. The desktop is using a wireless
keyboard and mouse and have Linksys Wireless-G PCI adapter, WMP54G v4,
installed. The notebook has Linksys Wireless-G notebook adapter, WPC54G
v2. Both adapters are configured with the same SSID, WEP, and are in
ad-hoc mode. I use Windows to configure the desktop adapter and see no
way of setting a channel. The notebook is configured using the Linksys
software and is set to a certain channel. Latest drivers are installed.
Both computers have a different computer name and belong to the same
workgroup. There are two problems. One, with the desktop on and after
the notebook boots up, both computers shows they are connected to the
network. Then, the notebook will cycle between network available and
unavailable every 3 seconds. The desktop will show network unavailable
only. Problem two, if I do get a stable connection, the desktop can see
both computers on the network, but, the notebook does not see any
computers, even itself. There are error messages about not having
permission accessing the workgroup. Any suggestions to fix the two
problems?

whiz