[Kmymoney] Backup to external usb

[Sawdust]

I am in transition from Windows to Ubuntu 12.04. I am also moving from 
Quicken to KMyMoney.  I have been able to "Save" and then backup to a 
usb drive. That changed this morning when I tried to back up to my usb 
drive. Initially the error pertained to backing up to the usb device. 
Now I get an error that states the drive can't be mounted. Since I'm new 
to Ubuntu and KMyMoney I don't which is causing the error.  Any 
assistance would be appreciated.     Steve