xmonad, xmonad-contrib & GHC_PACKAGE_PATH?

[William]

Hi all!

I'm trying to get xmonad to run, here's what I've tried:
I created a desktop profile for my user with:
(specifications->manifest '("xmonad" "ghc-xmonad-contrib" "ghc-hostname"))

I have "source .../desktop/etc/profile" and "exec xmonad" in my
.xinitrc and an xmonad config in ~/.xmonad/xmonad.hs.
I would have expected this to work, but running xmonad --recompile fails with:
xmonad: ghc: runProcess: runInteractiveProcess: exec: does not exist
(No such file or directory)

So I added ghc to the profile above, and now xmonad --recompile tells me:
Could not find module XMonad
(and a bunch of similar errors).

I tried adjusting GHC_PACKAGE_PATH to the profile's ghc
package.conf.d, but that didn't help.

So what's the correct procedure for using xmonad?
Do I need to fix a ghc version in my manifest? how do I find out which
ghc xmonad used?
If I need other libs (ghc-hostname for example) how do I specify one
that's compiled with the same ghc?
Or maybe something to be done in config.scm?

Thanks for your time,

-- 
Wonko7