multicore mclapply hangs

When I execute mclapply it creates the needed processes, but these
processes never begin computing anything, they just wait indefinitely.
I recently upgraded to version 2.9.1, which might have caused the problem.

I use Ubuntu 8.10.

sessionInfo()

R version 2.9.1 (2009-06-26)
x86_64-pc-linux-gnu

locale:
LC_CTYPE=da_DK.UTF-8;LC_NUMERIC=C;LC_TIME=da_DK.UTF-8;LC_COLLATE=da_DK.UTF-8;LC_MONETARY=C;LC_MESSAGES=da_DK.UTF-8;LC_PAPER=da_DK.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=da_DK.UTF-8;LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] multicore_0.1-3

loaded via a namespace (and not attached):
[1] tcltk_2.9.1 tools_2.9.1

Med venlig hilsen
Rune Schjellerup Philosof
Ph.d.-studerende, Statistik, IST, SDU

Telefon:  6550 3607
E-mail:   rphilosof at health.sdu.dk
Adresse:  J.B. Winsl?wsvej 9, 5000 Odense C