Nptl...missing

[nvalentine]

-bash-3.00# uname -a
Linux mail.zimbra.hq.*********** 2.6.16-xen #1 SMP Thu Apr 13 18:07:33 BST 2006 x86_64 x86_64 x86_64 GNU/Linux
-bash-3.00# yum list | grep nptl
Repository base is listed more than once in the configuration
nptl-devel.i386 2.3.4-2.19 installed
popt.i386 1.9.1-13_nonptl installed
rpm.i386 4.3.3-13_nonptl installed
rpm-libs.i386 4.3.3-13_nonptl installed
rpm-python.i386 4.3.3-13_nonptl installed
nptl-devel.i686 2.3.4-2.19 base
rpm-build.i386 4.3.3-13_nonptl base
rpm-devel.i386 4.3.3-13_nonptl base
-bash-3.00# cat /etc/issue
CentOS release 4.3 (Final)
Kernel \r on an \m

Yet the install reports "NPTL...MISSING".

Is this a 32-bit/64-bit library issue?