you will have to check your app descriptor file, the air version in application tag. Also, clean the project.Sometimes uncleared old references cause the same problem.I have faced similar issue once.
Thanks for the reply komal i did that but not cleared..one thing when i create the build from my flash builder the error happens.but the same project i used in another flashbuilder and create build..That build works fine...is there any chance for flash builder compiler problem.
I have the same problem and I can't figure why or how to fix it. Really need help here or I'm going to get nuts.
I think there may be flash builder compailer prolem.looking for exact solution.
Two things to check, if you're using an updater badge. The certificate (assuming you're created your own) needs to be the same one, i.e., the same machine, or the app won't know it's the same app and you'll have to uninstall before you can install again and, again using a badge, make sure the updater.xml info version is incremented as is the version in the descriptor file.