Success! Looks like we've fixed this one. According to our records the fix was applied for
Sencha - Ext JS Dev Team
This is being caused by a know issue with the compiler failing to detect dependencies on the core class system for classes that do not extend any base class. It has been resolved recently, and we hope to have a refresh build available soon with the fix.
As a workaround until then, however, you should be able to add the following comment directive at the top of ResultSet.js in the ext/src directory for this application:
This will indicate to the compiler that ResultSet.js requires the foundation set of files from the framework and will prevent ResultSet from being sorted before Ext. As both the compiler and app build commands draw sources directly from the raw framework source tree for builds, app build should start working once this tag has been added.
Thanks for the report! I have opened a bug in our bug tracker.