jackd won't start: "Cannot create thread 1: Operation not permitted"

The following terminal output sure describes this bug in great detail:

kenny_strawn@kenny-desktop:~$ jackd
jackdmp 1.9.7
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2010 Grame.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
Cannot create thread 1 Operation not permitted
Cannot create thread 1 Operation not permitted

usage: jackdmp [ --no-realtime OR -r ]
               [ --realtime OR -R [ --realtime-priority OR -P priority ] ]
      (the two previous arguments are mutually exclusive. The default is --realtime)
               [ --name OR -n server-name ]
               [ --timeout OR -t client-timeout-in-msecs ]
               [ --loopback OR -L loopback-port-number ]
               [ --port-max OR -p maximum-number-of-ports]
               [ --midi OR -X midi-driver ]
               [ --verbose OR -v ]
               [ --clocksource OR -c [ c(ycle) | h(pet) | s(ystem) ]
               [ --replace-registry ]
               [ --silent OR -s ]
               [ --sync OR -S ]
               [ --temporary OR -T ]
               [ --version OR -V ]
         -d backend [ ... backend args ... ]
               Available backends may include: alsa, dummy, freebob, firewire or net

       jackdmp -d backend --help
             to display options for each backend

kenny_strawn@kenny-desktop:~$ jackd -R
jackdmp 1.9.7
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2010 Grame.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
Cannot create thread 1 Operation not permitted
Cannot create thread 1 Operation not permitted

usage: jackdmp [ --no-realtime OR -r ]
               [ --realtime OR -R [ --realtime-priority OR -P priority ] ]
      (the two previous arguments are mutually exclusive. The default is --realtime)
               [ --name OR -n server-name ]
               [ --timeout OR -t client-timeout-in-msecs ]
               [ --loopback OR -L loopback-port-number ]
               [ --port-max OR -p maximum-number-of-ports]
               [ --midi OR -X midi-driver ]
               [ --verbose OR -v ]
               [ --clocksource OR -c [ c(ycle) | h(pet) | s(ystem) ]
               [ --replace-registry ]
               [ --silent OR -s ]
               [ --sync OR -S ]
               [ --temporary OR -T ]
               [ --version OR -V ]
         -d backend [ ... backend args ... ]
               Available backends may include: alsa, dummy, freebob, firewire or net

       jackdmp -d backend --help
             to display options for each backend

kenny_strawn@kenny-desktop:~$ jackd --loopback
jackdmp 1.9.7
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2010 Grame.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
Cannot create thread 1 Operation not permitted
Cannot create thread 1 Operation not permitted
Segmentation fault
kenny_strawn@kenny-desktop:~$ jackd --loopback --midi
jackdmp 1.9.7
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2010 Grame.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
Cannot create thread 1 Operation not permitted
Cannot create thread 1 Operation not permitted
Segmentation fault
kenny_strawn@kenny-desktop:~$

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: jackd 5
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic 2.6.38.7
Uname: Linux 2.6.38-10-generic x86_64
NonfreeKernelModules: wl
Architecture: amd64
Date: Tue Aug 16 09:33:33 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: jackd-defaults
UpgradeStatus: No upgrade log present (probably fresh install)