ghci crash (illegal operation)

I'm on NT 4 sp3 with ghc-5.01 thrill-seeker's release.
Under ghc --interactive, I get an illegal operation
when I run the following session. I'll attach the file
scratch.hs which contains the offending code. Feel free
to comment on the code itself, if you have the time. :-)

Administrator@BRK /NextGen/src/magellan/src/haskell
$ ghc --interactive
   ___         ___ _
  / _ \ /\  /\/ __(_)
 / /_\// /_/ / /  | |      GHC Interactive, version
5.01, for Haskell 98.
/ /_\\/ __  / /___| |      http://www.haskell.org/ghc/
\____/\/ /_/\____/|_|      Type :? for help.

Loading package std ... linking ... done.
Prelude> :load scratch
Compiling Main             ( scratch.hs, interpreted )
Ok, modules loaded: Main.
Main> foo <- findFirstAvailName "foo"

Administrator@BRK /NextGen/src/magellan/src/haskell
$

Trac metadata

Trac field	Value
Version	5.0
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	ResolvedFixed
Component	Compiler
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