> [...]
> OK so the application is called terramodel and the project files from
> that app are called [name].pro
>
> So if I highlight name.pro in ztw and hit O to open [name].pro in
> ztree it opens the application with name.pro loaded.. situation normal.
>
> But if I try to start the application from the desktop icon or by
> double clicking on name.pro in explorer it comes up with that message
> about needing admin rights.
> [...]
just a blind guess:
Seems that you have Windows UAC (user access control) activated and tarramodel.exe needs admin rights to run, thus you get the message about needing admin rights, when you double click on name.pro file from within explorer.
Do you start ZTree with admin rights as well? IIRC this will allow you to start any other file *from within ZTree* without further requests for admin rights.
Bernhard