The customization of the Quick Properties dialogue no longer works. The error message Microsoft .NET framework has an "Unhandled exception error occurs" message.Any ideas of how to solve this PLEASE!!

Not sure how one actually affected the other.  I'd uninstall then reinstall .NET framework and see if that solves the problem.Did you visit the AutoDesk website and search on the .NET framework error message?  Maybe someone has had a similar problem and found an answer for it already.

Thanks for your quick reply.We have uninstalled and re-installed.We got feedback from Autodesk but nothing has helped.Some on the machines in the office still work perfectly and others don't. We have compared machines but just cannot come up with a solution.

What exactly did you uninstall/reinstall?  Was it .NET Framework?  Please don't tell me you uninstalled/reinstalled AutoCAD.

The whole problem started when the firm's server was replaced with a Linex server. We had to re-install AutoCAD on all machines after that. Hence the customization stopped working. So we re-installed .NET framework. What is puzzling is that the one machine still works perfectly.

Then it sounds like the customized CUIx is the problem.  Restore the original CUIx and test the computer.  What happens?