problem compiling programs with monads with ghc-6.4

[Konovalov, Vadim]

Dear all,

When I compile simple programs with monads, I receive following error:

example18.o(.text+0x2de):fake: undefined reference to
`ControlziMonadziCont_zdfMonadContCont_closure'
example18.o(.text+0x422):fake: undefined reference to
`ControlziMonadziCont_zdfMonadContCont_closure'
example18.o(.text+0x16f5):fake: undefined reference to
`__stginit_ControlziMonadziCont_'
example18.o(.data+0xa8):fake: undefined reference to
`ControlziMonadziCont_zdfMonadContCont_closure'
example18.o(.data+0xe8):fake: undefined reference to
`ControlziMonadziCont_zdfMonadContCont_closure'

When I do 
ghc E:\apps\ghc-6.4\libHSmtl.a -o example18.exe example18.hs
all is fine.

For some reasons, libHSmtl.a is not seen by default.

What I am missing?

I feel this is configuration problem, but I afraid editing "package.conf" or
alike, because I'll probably make situation worse.

TIA.

Best regards,
Vadim.