Trying to get an app building in using the new Sencha Cmd v3, and having issues.
Can't seem to get a decent error message out of it...

I have a three stage process:
  1. Make symlinks so that filesystem looks like web structure.
  2. Create JSB3
  3. Build it
In SDK Tools v2 creating the JSB3 used:
sencha create jsb -a http://localhost/TransferGateway/index_build.html -p ATG.jsb3
Now I'm trying (in Cmd v3):
sencha --debug app resolve -uri http://localhost/transfergateway/index_build.html -output-file ATG_cmd3.jsb3
Getting output:
Sencha Cmd v3.0.0.250
[ERR]           null

        at com.sencha.exceptions.BasicException.wrap(BasicException.java:43)
        at com.sencha.cli.Command.dispatch(Command.java:104)
        at com.sencha.cli.Commands.dispatch(Commands.java:49)
        at com.sencha.cli.Commands.dispatch(Commands.java:49)
        at com.sencha.command.Sencha.main(Sencha.java:71)
Caused by: java.lang.NullPointerException
        at com.sencha.command.app.AppCommands$ResolveCommand.execute(AppCommands.java:197)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at com.sencha.cli.Command.dispatch(Command.java:78)
        ... 3 more

I have no idea how I'm going to do the next step, building the JSB3.
Trying to point it at an older version either does nothing or give me:
[ERR]           Please ensure this command was executed from a valid application directory
[ERR]           Unable to locate 'app.dir' config property from sencha.cfg
I do not use Sencha Architect, this is an existing product.
Can I generate an app.dir or something? What is its format?

Appreciate any help.