You can check the integrity of your files by checking their MD5 hashes using a program such as HashCalc.
The MD5 of the 'simpleviewer.zip' file downloadable from this page is: 28b0535cb6a7b3bad1d67062843b115f and the MD5 of the 'svBuilder.air' file inside the zip package is: b0e50881945cb8f494c25838dc3c7a00
If the MD5 hashes of your files do not match the ones above, then try redownloading the 'simpleviewer.zip' file from this page.
Try using a different browser than that which you used for your previous attempt (Firefox, IE, Safari, Chrome).
Also, if you are using a download manager, try switching it off or, conversely, if you are not using a download manager, try using one (such as Free Download Manager).
If the MD5 hashes of your files do match the ones above, then there is nothing wrong with your files and the problem lies elsewhere, most likely with your Adobe Air installation.
Try uninstalling Adobe Air and reinstalling the latest version available from here.
You could also try turning off User Account Control if you are a Windows user.
If you continue to experience difficulties, perhaps the Troubleshoot AIR installation page may help.
SimpleViewer Support Team