I made a bit of a progress and I want to share what I did.
When you get errors like this on the LogCat, they are saved on \$PROJECT_PATH/obj/local/armeabi where \$PROJECT_PATH is the path to your cocos2d-x android project. To symbolicate the messages to something understandable, you can use the ndk-stack tool.
Open up the Terminal (or Cygwin, not sure though) and type in
adb logcat | ./ndk-stack -sym $PROJECT_PATH/obj/local/armeabi
\$ANDROID_NDK is the path to your android NDK
PROJECT_PATH is the path to your cocos2d-x android project
After that, you will get a stack trace which points to certain files and line number where the crash occurred. Something like this:
********** Crash dump: **********
Build fingerprint: 'generic/blaze/blaze:2.3.4/GINGERBREAD/6.3.1_user_4107920:user/release-keys'
pid: 16346, tid: 16354 >>> com.mycompany.myapp <<<
signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 00000000
Stack frame #00 pc 002a13f0 /data/data/com.mycompany.myapp/lib/libmyapp.so: Unable to locate routine information for address 2a13f0 in module
Stack frame #01 pc 0012e81e /data/data/com.mycompany.myapp/lib/libmyapp.so: Routine updateNode in jni/../../Classes/TowerObj.cpp:150
Stack frame #02 pc 000f3648 /data/data/com.mycompany.myapp/lib/libmyapp.so: Routine updateLayer in jni/../../Classes/BuilderLayer.cpp:107
Stack frame #03 pc 0010bb94 /data/data/com.mycompany.myapp/lib/libmyapp.so: Routine updateGame in jni/../../Classes/MainGameLayer.cpp:172
( more here pointing to cocos2d-x classes )
From the dump above, you can see that on Stack frame #01 points to TowerObj.cpp:150, so I can now go to TowerObj.cpp at line 150 and fix stuff.
Hope this helps.