Recently, when I developed an simple android application for version 3.0 (API 11) and tried to run this on version 2.3, I got this wierd problem. The error looks something like:
There is a problem parsing the package.
The solution to this problem was to specify the minSdkVersion to a version on which you are trying to run the application. In my case version 2.3.
Edit your manifest file which contains the line
or whatever is preferrable for you.