Big windows-mac troubles

[Vince]

This is half mac and half windows but it is really troubling me.....so 
here we go, any help is greatly appreciated::

The machines:
Ti book 667/512mb/OS 10.2.4
Celeron 400/256mb/Win2k Server service pack 2

The backbone:
smc wireless and ethernet router 10/100 with all cat 5 cables
win box connected via ethernet
mac connected to router via airport card/wireless

Problem:
I'm trying to access files on the win2k server in my room via the smb 
client built into os x.  I have a significant amount of storage space 
in the server and would like to use the file sharing capabilities to 
store backups of files on the server.  My problems are....

1. I cannot copy large files TO the win2k server, the transfer errors 
our and stops.
2. I cannot copy large files or folders FROM the win2k server, the 
transfer freezes, errors out and stops
3. Both of the above conditions caused the mac finder to hang for 
several minutes and then subsequently become semi unstable i.e. the 
finder needs to be relaunched and sometimes doesnt restart....

What I've done so far:
1. Fresh format C: and install of win2k server on the win box
2. Set up only ONE account on the win2k server, the admin account
3. Created a couple shares on win2k by rt-click -> share ect...
4. I can see/log into/and browse the shares from the mac
5. The permissions on the win2k box are not modified, the administrator 
has write/read permissions for everything.
6. Disabled the win2k server extra services (i.e. DHCP, DNS, and WINS 
services so they dont conflict with the router)
7. All the file transfers error out.....and I'm at a loss as to what to 
do next.....

thanks!

Vince