ISOGEN Error XCHG0000: User Cancelled

We are using Plant Design V8i SS4 and ISOGEN.

We are trying to pull out an Isometric but by pressing the button Generate ISO, we get the Error message before we can see anything being a problem :

This message box pops out even before the Selection Box appears.

Everything was fine the day before.

The problem is specific to a particular machine, no matter what model or project we try to pull out the iso from.

If we extract from another machine (same projects or models) everything is fine. We backed up to last week and changed bentley files with those of a working PC but still the same results. 

Any help or anything that we could check before reinstalling the PC is welcome,