I have just solved a similar problem for myself. As per my answer on BlackBerry RIMAPPSA2 signing key required — why?. I have updated this answer to help in case of future searches on similar words...
This might be due to a bug in Eclipse or RIM. You might not be using the RIMAPPSA2 classes.
OK, so its hard to believe but this page might fix the problem for some:
Basically its a bug, and by changing the Application Descriptor, saving, removing & re-adding the JAR file, the problem is fixed.
Follow-up #1 - might not work:
The above solution enabled me to build & sign the app. Unfortunately the app won't run on the phone Module 'MyApp" attempts to access a secure API.
Follow-up #2 - this worked for me:
I documented a full solution that worked for me here:
In my case, I was importing my own JAR file, and I needed to set that project's build type to be a MIDLET
. Setting it as LIBRARY
or APPLICATION
caused problems.