I know it is a very small user case but I can confirm an issue much like what is posted here
https://groups.google.com/forum/?fromgroups#!topic/phonegap/apQEO2pRdNo

Essentially using Ext.ajax to load a large file will return a Status of 0 on Android 2.2. It works fine on Android 2.3 and above though. I know this is a Ext issue as if I switch over to jQuery $.ajax and load the exact same file it works without a problem.

It would be nice to not include jQuery into my application but for now that's the only way it will work loading large local files with ajax.