sencha app upgrade -ext - problems accesing old version of ext?

I'm having no luck with upgrade -ext. Initially I was getting:

Code:

$ sencha app upgrade -ext
Sencha Cmd v5.0.0.116
[ERR] Cannot satisfy requirements for "ext"!
[INF]    The following versions are available:
[INF]    The following versions can be satisfied:
[ERR]    The following versions cannot be satisfied:
[ERR]       framework package dependency: ext@4.2.2.1144 (No matches!)
[ERR] Cannot resolve package requirements
     at com.sencha.tools.pkg.PackageResolver.getPackages(PackageResolver.java:168)
     at com.sencha.command.environment.FrameworkEnvironment.loadFrameworkPackage(FrameworkEnvironment.java:179

Specifying a path to ext was failing also. I came across a post that showed how to load the package manually (http://ift.tt/1f1IjLh) and now I get:

Code:

$ sencha app upgrade -ext
Sencha Cmd v5.0.0.116
[ERR] Cannot satisfy requirements for "ext"!
[INF]    The following versions are available:
[INF]       5.0.0.736 ( ... compatible back to 4.0)
[INF]    The following versions can be satisfied:
[ERR]    The following versions cannot be satisfied:
[ERR]       framework package dependency: ext@4.2.2.1144 (No matches!)
[ERR] Cannot resolve package requirements
     at com.sencha.tools.pkg.PackageResolver.getPackages(PackageResolver.java:168)
     at com.sencha.command.environment.FrameworkEnvironment.loadFrameworkPackage(FrameworkEnvironment.java:179)
     at com.sencha.command.environment.AppOrPackageEnvironment.loadFrameworkConfig(AppOrPackageEnvironment.java:56)

I am using OS X (10.9.2) and I have no proxy settings configured for Java (7 Update 55).

Am I missing a step somewhere? In both cases above the problem is an inability to access the version of ext I am attemptng to upgrade from - why does the upgrade to 5.0.0.736 need access to 4.2.2.1144?

Any advice on how to proceed?

Thanks,

Scott