Using ~amd64 (only on the computer with an Intel processor), I can't advance past the "Select Style" screen (I select either "Single" or "Solo", the selections vanish off to the side as normal, but the counter in the upper right corner still counts down. It plays the sound for changing screens both when I press Enter and when it finishes counting down). Nothing looks suspicious in the info.txt or log.txt and it was working probably 6 months ago, so perhaps some package versions have changed.
Created attachment 214367 [details, diff] Proposed patch to fix this issue Taken from http://aur.archlinux.org/packages.php?ID=5453 (specifically http://aur.archlinux.org/packages/stepmania/stepmania/stepmania-3.9-select_style.patch)
I have had the same problem on amd64 (Intel CPU). Confirmed. Patch works. Instructions how to apply taken from here: http://www.stepmania.com/forums/showthread.php?p=159406
Applied to -r2.