Hey, I have this problem.

I figured out how to mount a windows ntfs file system on another portion of my harddrive. I took some mp3s from there, and transferred them to my linux partition. However, when i try to add them to the library of rhythmbox it tells me that they are not audio streams... Can I get these mp3s to play in linux?
Thanks

Did you install the codecs? By default, Ubuntu won't play mp3 (and a whole lot more media files). Please, read the Ubuntu Guide to install the codecs correctly.

Regards!

First of all, thank you for your help.

I checked out the ubuntu site you mentioned, which helped me get the mp3s onto my linux partition in the first place, and they told me to do this:
sudo apt-get install gstreamer0.10-ffmpeg gstreamer0.10-gl gstreamer0.10-plugins-base \
gstreamer0.10-plugins-good gstreamer0.10-plugins-bad gstreamer0.10-plugins-bad-multiverse \
gstreamer0.10-plugins-ugly gstreamer0.10-plugins-ugly-multiverse w32codecs

I did, but there was an error message saying that:

Package gstreamer0.10-ffmpeg is not available, but is referred to by another package.

I also tried the synaptic package manager, found an mpeg package, and installed it.

However, I am still getting the same error when i try to add mp3s: this file is not an audio stream.

I'm going to guess that you were right, that it was a problem relating to audio codecs.

I download xmms, and it played without a hitch. I figure it downloaded the codecs with it. I still don't know why rhythmbox would not use the codecs I installed (if that was the problem) but I prefer xmms anyways. Thanks for your help.

If you were getting errors for missing packages like that you might not have all the necessary repositories enabled. On the same page linked to before it has instructions for this. If you did that already, I don't know what the problem was, but glad you found a different way to get it working.

Theres a general legal and ethical prolem with propietary codecs and drivers in gnu linux. I have the easylinux installer in my signature, it will set everything up automatically. That should make mp3's wma and so on work on all players.
Have fun.