My "ri" died!

Hello,

Without any real explanation, all of the sudden, my “ri” died:

$ ri
dyld: NSLinkModule() error
dyld: Symbol not found: _st_init_numtable
Referenced from: /usr/local/lib/ruby/1.8/powerpc-darwin8.3.0/
syck.bundle
Expected in: flat namespace

Trace/BPT trap
$

It was working absolutely fine a little while ago.
Ruby still works fine.

Any hints?

Merc.