Turns out the issue with IO::LockedFile is Solaris specific. I know, I know - shocking. I installed it fine at home on my Linux box. I seem to recall reading somewhere at some point that fcntl could be wonky on Solaris. I'll report it when I'm back at work on Monday.
In other news I've posted my concerns regarding the speed of Ruby 1.8.0. In 7 of the 9 benchmarks I ran, it was *slower* than 1.6.8. Hopefully, my post will stir up some focus on optimizations (and not prematurely).