Hello,
Please can you check if the following registry key exists on your PC:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\DynamicsNav71
It should contain the following String Value:
Value name: DisplayVersion
Value data: 7.1.35473.0
If the above doesn't exist, add manually and try running the Zetadocs Express installer again. Please let me know if this resolves the issue or not.
Kind regards,