[CentOS] Cannot mount NTFS filesystems under Xfce4

I have installed the following 2 packages on Centos 5.6, and 
used GParted to successfully create an 8GB NTFS partition, 
on some unused HDD space.

Installed Packages
Name       : ntfsprogs
Arch       : i386
Version    : 1.13.1
Release    : 6.el5
Size       : 1.1 M
Repo       : installed
Summary    : NTFS filesystem libraries and utilities
URL        : http://www.linux-ntfs.org/

Name       : ntfsprogs-gnomevfs
Arch       : i386
Version    : 1.13.1
Release    : 6.el5
Size       : 20 k
Repo       : installed
Summary    : NTFS GNOME virtual filesystem module
URL        : http://www.linux-ntfs.org/

I'm running Xfce 4, and when I try to mount the NTFS file 
system, I get an error box with 'ntfs - unknown filetype'

I've done a complete reboot of this box.

Are there some packages I have missing?

Kind Regards,

Keith Roberts

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