The error "Unable to launch c:...Tempmdac_typ_en.exe" occurs on some systems triggered by the combination of how the setup is run on certain machines and how the machines are configured internally.
Following is a list of common causes of this error:
1. The setup does not have access to the "Temp" directory or if the default "Temp" directory of the machine is not clean or does not have enough space to run the setup.
2. There is a corrupted version of Windows Installer engine on the machine.
1. Make sure that the default "Temp" directory is clean and you have write access to the "Temp" directory .
2. You will need to install (or reinstall) the latest Windows Service Pack to update the Windows Installer Service on that machine. (eg. install Service Pack 4 on Windows 2000, etc.)