That bug has been opened on https://launchpad.net/distros/ubuntu/+source/rhythmbox/+bug/33872

"*Ubuntu 6.04 Dapper (Flight 4)
*Rhythmbox 0.9.3.1
*GStreamer 0.10

For some reason song slider is greyed out when I'm playing mp3
songs from my windows NTFS drive. Seeking works as expected
when playing songs from /home ext3 partition or from iPod (fat?).

I tried running Rhythmbox using -d flag, but slider callback doesn't
seem to publish any events.

NTFS drive is defined on fstab with params
ro,auto,nls=utf8,umask=0222 0 0
...
> Thanks for your bug. Do you still have the issue? Does it work with totem-gstreamer by example?
...
Yes, slider works as expected totem-gstreamer.

It's a rhythmbox issue. When I look one of the song's properties, Duration is 0:00 and Bitrate is Unknown. Same for goes for every mp3 I have..
...
> Do you have gstreamer0.10-plugins-ugly installed? Does "gst-launch-0.10 playbin uri="file:///path/to/my/musicfile.ogg"" play it correctly? Does rhythmbox -d says anything about the song length? Does it happen if you copy the .mp3 on your linux partition?
...
Yes, gstreamer0.10-plugins-ugly and gstreamer0.10-plugins-ugly-multiverse are both installed.

gst-lauch-0.10 command plays .mp3 file correctly from NTFS partition. Running rhythmbox on debug mode doesn't output anything related to song length.

When I move the .mp3 file to ext3 partition and play it from there, song slider works as expected. Seems to have something to with NTFS or non-native partitions maybe."