Can't use su under VNC after reboot

[lsgko]

Using FC4, I added a VNC user then restarted the VNC server and was able to connect using the vnc client. Everything worked perfect, I could use su. But after a reboot, I can no longer use su. It gives the error: "su: /bin/bash permission denied" and brings me back to the prompt. I only have su problems when using the VNC client.

Any ideas?

Thanks in advance.