It seems it is the same as #7470. Please try the following solution.
In [ruby-core:50377] [Backport93 - Backport #7470], usa (Usaku NAKAMURA) wrote:
It's already fixed on the repository, but not released yet.
Check out r37593 or later from ruby_1_9_3 branch, or simply patch the revision by hand, please.
IMO the simplest way is downloading random.c of the revision and replace the file in p327 package.