VNC client problem connecting to linux vnc server

I have used chicken of the vnc and the other one available, I think it's called Vnc viewer to try and connect with my vnc server at work. So on my home network I have my work PC laptop that can connect no problem, and stay connencted for hours using tightVNC. I try to do the same thing on from my iBook, and most of the time it will connect for maybe 5 seconds, I can start working, and then it will say connection closed. Sometimes it works for a 5 minutes, sometimes not even 5 seconds. It's almost like there is some kill signal that keeps being sent out, but like I said it only happens on my iBook, not on my work PC. Both are connected wirelessly to an airport express, but I had the same problem using a different wireless gateway too. Any ideas?