For information purposes:

It looks like the I-Planner shortcuts in a multi-user standalone install are only placed on the desktop and in the Start menu of the user logged in when the install is done - not in All Users, as the ITR shortcuts are placed. This affects non-domain machines when you create a new user account. I only found this out because a teacher left and I created a new user account for their replacement on the staff laptop and they didn't have the shortcuts for the planner. Once I'd copied the shortcuts across, the program worked fine.

So if you are doing a standalone multi-user install, copy or move the shortcuts to the appropriate folders in the All Users folder in Docs and Settings once the install has completed.