c:\Users\xyz>GHCI
GHCi, version 7.0.1: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package ffi-1.0 ... linking ... done.
Prelude> :cd C:\Users\xyz
Prelude> :m +Address

<no location info>:
    Could not find module `Address':
      it is not a module in the current program, or in any known package.
Prelude> :m +Address.o
syntax:  :module [+/-] [*]M1 ... [*]Mn
Prelude> ^C
c:\Users\xyz>
Prelude>
c:\Users\xyz>
c:\Users\xyz>
Prelude>
c:\Users\xyz>
Prelude>
c:\Users\xyz>
Prelude> dir
 Volume in Laufwerk C: hat keine Bezeichnung.
 Volumeseriennummer: 4A51-A50C

 Verzeichnis von c:\Users\xyz

25.11.2010  22:52    <DIR>          .
25.11.2010  22:52    <DIR>          ..
[***output removed (cmd.exe was listing my directory's contents here)***]

c:\Users\xyz>
Prelude>
ghc.exe: panic! (the 'impossible' happened)
  (GHC version 7.0.1 for i386-unknown-mingw32):
        thread blocked indefinitely in an MVar operation

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug