ZWCAD is not a valid win32 application

I installed a freeware ZWCAD installer trial version a free download in the net. As the installation was finished this message appeared on the screen

D:Setup.exe
D:Setup.exe is not a valid Win32 application.
Because of that error I decided to stop the installation and removed from the control panel. As I go on to my next installation and this time an Adobe Photoshop Cd installer. When I started to install the said software and finished the setup cannot be open and the error came out again.
I did the restart options to verify if the installation is completed but still the error is there.
How on earth can we remove the so called error?
Can you identify the problem?
Please help thanks!
