Install/Update Apps gives "Insufficient Storage Available" error, although I already cleared the cache and other data
I had this same problem and this fixed it


go to "/data/app-lib/APP-PATH(that has this error)/lib" and delete.
install/update the apk app.


If this doesn't work try going to "/data/app-lib/APP-PATH(that has this error)" and delete all the folder (but you must begin by their sub-folder then the folder itself, because you cant delete the folder of this APP-PATH directly without deleting their sub-folder first

The reason for this is that for android 4.2,+ google create a new lib folder for the apps in "/data called /data/app-lib/" and there is a symlink from "/data/data/APP-PATH/lib" to this folder which is the most culpable of this error.

I came by this knowledge here http://forum.xda-developers.com/showthread.php?t=2443267

Like I said it worked for me..