rdesktop - local HDD share problem

["Seshadri T N" <seshadri.tn@gmail.com>]

 I use rdeskop (running on lenny) to connect to my
school. I tried to share the debian drive with the "-r
disk:bkup=/mnt/backup/ " option. When I connect to my school, I am able
to use the local debian HDD for 40 seconds or so. Then an error throws
up saying "tsclient://..... you do not have permission to access the
drive".... I am a little puzzled. How come it allows me to access the
drive for a couple of seconds and then it throws up the error? Can
somebody please help me solve this problem so that I can share my
local drive to the remote machine comfortably. 

Thanks
Sesh