Inconsistent Link Between WinXP Client and Server2003

I have shared a folder in server to be accessed by this particular user
account (let say user1). There's $ sign at the end of folder name (let say
foldername$). I've set the foldername$ to be shared by everyone while in
Security full accessed is given only for user1. My data file for the
application is in this folder. The problem is the inconsistency connection
from the client to foldername$ in server. Sometime i can open the foldername$
from the client but later on i can't. i'm using \\IPAddress\foldername$.
I've added IP address and ServerName at the last line in client's
c:\windows\system32\drivers\etc\hosts yet the problem is still the same.
The server is Win2003 and the client is WinXP. In between there are 3
switches.