Can't unmount floppy

[rgm at htt-consult.com (Robert Moskowitz)]

Using the Disk Management GUI.

I mounted the floppy

copied a file to it by dragging from one Nautilus window to another

Then I tried to unmount the floppy and got an error that the device 
(/media/floppy) was busy.

This is not the first time this has happened to me.

And it does not happen all the time.  In fact, yesterday I did the exact 
same steps with no problem.