If you want to use that text variable in a field that accepts tokens, the syntax would be
{TXT:window}
In this case, however, you'll need to use the "Perform a Window Function" action(which takes text variables directly as well as tokens) to switch command targets.
E.G.
Display window 'window' as [Normal]
For more information, check the "Advanced Targeting" section of VoiceAttackHelp.pdf, pages 184 to 187.