I solved by deleting the file debug.keystore in the folder %user_profile% .android, and recompiling the Android project... the problem seems to be resolved.
if it still does not work, you try the following command
keytool -genkey -v -keystore myapp.keystore -alias myapp -keyalg DSA -keysize 1024 -validity 10000
In my case, the problem occurs when I use export wizard on Eclipse. the following command is no problem(MyApp.apk is unsigned).
jarsigner -verbose -keystore myapp.keystore MyApp.apk myapp
My other keystores are SHA1withRSA algorithm, and no problem.