If you are trying to download and install your TaxAct software, but when you click to run the installation file you get a "Not a valid Win32 application" error, this may be due to an incomplete download file. A temporary or part file is created while the file is downloading. This is usually designated with something added to the filename, for example "_part."
Make sure the download is complete so that you have the completed installation file to run. You can download again. Check your browser for any messages showing progress of download. You can change your browser settings to run the file instead of saving it. You can also try downloading with a different browser.