NetBeans is a handy IDE that supports a whole bunch of languages. Fortunately - Android development is one of them. Not so fortunately - plugin is a big buggy and problematic.
Check this list out - perhaps your problem is described here.
Known Issues
My AndEngine project won't start on the device/emulator
If your project crashes as soon as it starts it probably means you're missing andengine.jar. Add it and other extensions you require to lib/ folder under your project, reference them as jars from NetBeans and add this to build.xml after <import file="nbproject/build-impl.xml"/> line:
<target name="-pre-jar">
<copy todir="${build.classes.dir}">
<fileset dir="lib/" />
</copy>
</target>
Assets are not found even if I have them in my assets/ folder
Problem
NetBeans Android plugin creates buggy project by default that does not include assets when building .apk packages. This means that Android and AndEngine cannot load assets because they are simply not there.
Solution
Edit your nbproject/project.properties file. Find "assets.dir=" line. Replace it with this:
assets.available=true
assets.dir=assets
asset.dir=assets
