interpretBCO: unknown or unimplemented opcode 61764

I just hit an internal compiler error:

$ ghci blatt2a6.hs 
   ___         ___ _
  / _ \ /\  /\/ __(_)
 / /_\// /_/ / /  | |      GHC Interactive, version 6.6, for Haskell 98.
/ /_\\/ __  / /___| |      http://www.haskell.org/ghc/
\____/\/ /_/\____/|_|      Type :? for help.

Loading package base ... linking ... done.
[1 of 1] Compiling Main             ( blatt2a6.hs, interpreted )
Ok, modules loaded: Main.
*Main> pretty startn merk1
<interactive>: internal error: interpretBCO: unknown or unimplemented opcode 61764
    (GHC version 6.6 for i386_unknown_linux)
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
Abgebrochen

Trac metadata

Trac field	Value
Version	6.6
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown
Architecture	Unknown