Can only mount mp3 player once

[Raphael Roberts Ubuntu Mailing List]

This is my first post to the ubuntu list so I hope it works!
I am having a problem with a mp3/mp4 player that I have purchased.
I have managed to mount the device once and copy files to/from it.

Now I cant mount it again. When the device is plugged in I can see it
sitting there if I go to "places... computer" and it lists as "IHT680
PMP" next to floppy drive, Filesystem etc.

However when I try to double click on it I get a message saying: 
"Error: could not lock the mount directory. Another pmount is probably
running for this mount point."

I have tried fiddling with pmount --unmount command but Im new to linux
and dont really know what I am doing :)

I think the issue is that it mounts but does not unmount properly, so
next time I plug it in I cant access it.

Could anyone let me know what I should try next?

I dont know if it helps, but the player has two memory in it, an SD card
and inbuilt memory. Both of these I could access once. My /dev folder
contains entries for sda sda1 and sdb (dont know if thats relevant?)