Sybase ASA 8 Connected users.

I am currenting using Adaptive server 8.02.4361 with a number of users conneted to one database server from a number of remote sites using VLANS.

When in Sybase central, I need to use the 'All connected users' view to see who I have logged in at any given time, however I have two users from one of my branches that do not show as connected, even though I know they are, and this is confirmed by said users.

Are there any known reasons of bugs to cause this, or am I missing something simple. All other users are connected correctly, and all users have been set up in the same manner with the same database client application.