The powerchords rhythm patch? Are you holding down a note/chord in the chord detection area while pressing the strum keyswitches, so that the notes will be fretted? Otherwise the strum keyswitches will just play across the muted strings.
i'm having a little trouble with the chord strum patterns - if i put a bar in the first spot on the strum map, and then draw that trigger note in at time zero in my DAW, the chord will not play at time zero. if i use a drum pattern which has a bar in the second column, then the chord will be played at that second 16th time.
how do i trigger a chord to be strummed starting at time zero?
Because the strums occur across the beat rather than starting on the beat, you have to anticipate them by a 16th note or so. It's a little unintuitive, but if the strums started on each beat, varying the strum speed on different strums would make the rhythm sound unsteady. That's actually one of the reasons the strumming pattern system was discontinued in favor of a strumming palette method. The upcoming update includes a completely new approach, encompassing both strum keys and strum patterns, though.