Intermittent network fault/problem

This is what I'm trying to do ~ I have another building office that is
just across the parking lot. I want to be able to connect a computer
and a time clock device to the network in my main building.

I have a Windows 2003 server and about 10 PCs that are all connected
via a Wired Gigabit Switch at the main building. Things have been
running fine for over a year, until I attempted to add a set of
Linksys WAP-200 access points.

I setup the WAP-200 devices in Bridged Mode, setup WEP encryption on
them, and then attached one access point onto the Gigabit switch in
the main building. Went across the parking lot and setup the other
access point, put in a 10/100 switch, and connected the AP and the
computer.

We are able to surf the Internet with no problems with the computer
across the street, but after setting up the WAP-200 devices, I am now
getting a strange problem with some of my applications that are
running on my server ~ users get booted off in the middle of what they
are doing. (They are using Peachtree Accounting, and another program
JobBoss. The "Boot" is just an error in the program [Error number
3110 in Peachtree, and a really long error in JobBoss] that causes
them to close out the program.) They attempt to open a link to a
network drive (on the server) and it hangs for a second and then
opens. They can re-launch the application and it is ok for a little
while, until the hiccup comes back.

This problem didn't start until I added the APs.

I disconnected the AP that is on the Main Office switch, and the
problem went away.

Ideas?

John