Looks like we can't reproduce the issue or there's a problem in the test case provided.
Sencha Premium User
[4.1 B3] : form.Basic.setValues() gives error if the form has a radio group
Thanks for the report, we already have this one fixed up for the next release.
Twitter - @evantrimboli
Don't be afraid of the source code!
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Any guesstimate as to when this will be release (1 week, 2 weeks, 1 month)?