won't record video

[bvrush]

I'm having a problem recording video with my Treo 650. It was working fine until recently, and I don't know why it's not working now. When I press record I can see that the timer is not moving, even though the red recording indicator is on When I press stop and go to Media all I see is an icon with a red X. If I try to open the video it tells me " Warning......... Unable to display this video. It may be too large, corrupted or stored in an incompatible format."
I'm using a 1GB SanDisk memory card. I've tried reformatting it, and have tried another 512MB card I have, but still can't get the video to work. I have 6.9 MB left on my device and 478.5MB left on my 1GB card.
The Camera and opening photos works fine. I'm just having a problem with the Camcorder.
Any help would be much appreciated. Thanks!

[bvrush]

I think I figured out what the problem is. I removed some MP3s from my memory card, which created more free space. Now the Camcorder works. Even though I already had 478.5MB of free space the memory card was not allowing any more data. I had this problem when I was first adding MP3s to the card through an internal card reader in my computer. I have a 1GB card, but could only get it about half full. I could only get more MP3s on it by transfering them through Real Player on my computer.
Does anyone know how I can utilize all the free space on my card? It's a new card, and I've tried reformating it a few times.