The bug (2792) that caused this got fixed very recently (it would have prevented you from installing that package, as it requires much of the system to move forward).
Unfortunately, there's no way back. You're best off getting a copy of the latest OpenSolaris ISO image, burning it to a CD (or DVD, if it won't fit), booting off of it, and doing an image-update of the image on the hard drive. Danek
