I have the same problem when trying to build an apk.
When I run Sencha Cmd Setup, in the Setup Project and I point the framework to the sencha-touch-2.1.0 directory I have the following response from prompt.
The cd command cannot change directory to another drive and consequently the sencha command fails.
I know that exists an option in cd that can change drive and directory in one step: /D, so the command should be:
cd /D "Y:/path/to/project/"
Is it possible to implement this or we must wait the 2.2 release?