Hi disegno,
This sometimes happens when update finds something unexpected with your current installation, or when you are trying to carry out the update as a non-administrator.
progeCAD software can / should only ever be installed and updated with full system administrator privileges. Not doing so the first time can seriously mess up your installation with a "half-updated" system that may not update properly again - or worse - not run at all.
If problems continue, you can try to install the progeCAD update from the full version of progeCAD 2010 10.6.23 from download:
http://www.progecam.com/download/progeCAD_Professional_2010_CADDIT.exe
Keep in mind you most likely with have to completely uninstall and remove the current version of CAD software you have before installing the new full version
CAD download.