Many people come across this not a valid win32 application error and the following are some of the reasons for which the error is thrown.
The most common cause is the file getting corrupted. Especially, if you downloaded it from the internet, make sure that the file has been downloaded completely. Try re-downloading it again from other mirror sites and see if it works.
Another cause is hardware errors. If you run the program file from the CD then, make sure that the CD is in proper working condition and is not damaged in any way. Some times driver problems can cause such errors. In such cases try copying the file from the CD to your hard disk and run it. If the “Not a valid win 32 application” error persists then it may be due to other reasons.
If some other program is trying to prevent the execution then this might also result in such errors. For example, consider that the file is a virus. When the file is run, the antivirus scanner may prevent its execution due to the fact that it has found something wrong in it. Hence, it always good to scan a program before using it.
Windows incompatibilities can also result in such errors. Say the file is designed for a 64 bit OS and if you run it in a 32 bit OS then this “Not a valid win 32 error “is thrown.