IF I do everything the guide says to do for theming. It ends of this command error:

Code:
ext-react generate theme --name custom-theme --baseTheme theme-materialUSING sencha:  /usr/local/lib/node_modules/@extjs/reactor/node_modules/@extjs/sencha-cmd/bin/sencha
Using existing workspace at ext-react/workspace.json
Generating theme package...
[ERR] Error: spawn /usr/local/lib/node_modules/@extjs/reactor/node_modules/@extjs/sencha-cmd/dist/sencha ENOENT
    at _errnoException (util.js:992:11)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:190:19)
    at onErrorNT (internal/child_process.js:372:16)
    at _combinedTickCallback (internal/process/next_tick.js:138:11)
    at process._tickCallback (internal/process/next_tick.js:180:9)
    at Function.Module.runMain (module.js:695:11)
    at startup (bootstrap_node.js:191:16)
    at bootstrap_node.js:612:3
Error encountered. Could not read package.json for theme named: custom-theme