Hi There Potemkine,
Thank you for your time and effort, it is very much appreciated! The design checker at my side indicates no problems so I think you are right in the sense that the error you encountered on your side was probably data connection related. I'm sorry if I've have wasted your time
The question still remains though, why is the form behaving differently on different computers. I'm seriously starting to suspect my Windows 7 PC or a combination of Windows 7 and the network for a number of reasons.
a) It is the only PC on which I get an error
b) I have other perfectly normal forms which also have a problem opening on the Windows 7 PC.
c) An error only occurs when opening forms (All my forms are stored on a server and I use links / URLs which point to those forms)
d) If it is a design error I will most probably experience a constant problem and not a random problem - I don't know if this makes sense!
Thank you again
Johan