iOffline requires Adobe AIR to run. Unfortunately, you might have version 3.4 installed which has a bug that prevents iOffline from getting installed or updated.
While Adobe is fixing this bug, as a temporary workaround you can get iOffline to work by downgrading to Adobe AIR v3.3. This is an easy process:
- Go To > Control Panel > Programs and Feaures (in xp: Add or Remove Programs)
- Select "Adobe AIR" and uninstall the runtime.
- The link http://helpx.adobe.com/air/kb/archived-air-sdk-version.html allows you to download and reinstall the previous (3.3) version of Adobe Air.
- http://helpx.adobe.com/air/kb/archived-air-sdk-version.html to uninstall the current version (Double-click the "Adobe AIR Uninstaller", which is located in the /Applications/Utilities folder)
- reinstall the previous version of Adobe Air Runtime.