[xmonad] Strange spawnPipe error

[Brent Yorgey]

Hi all,

I'm getting my laptop re-set up (after installing a new hard drive
after the old one died).  I've got an up-to-date arch linux installed,
and darcs xmonad, using the same config that I had before.  However,
now when xmonad starts up it fails to start dzen via spawnPipe.
Instead, I get this error:

  createSession: permission denied (Operation not permitted)

Due to various debugging activites on my part it is clear that this is
being generated by the call to spawnPipe.  Anyone have any ideas?  I
could file this on the bug tracker but it is not at all clear to me
that it's an xmonad bug, I was just hoping someone might have an idea
what is wrong.  I don't really understand what spawnPipe is doing
under the hood and what might go wrong.

-Brent