Okay, I'm not sure how I did this but I'll try.
I had the same problem as you some time ago.
I could use the scanner once but not again.
If I wanted to use it a second time I had to reboot.
(i think that's right) I found a LINK that delt with the problem.
I had to use a command if I wanted to use it over and over without rebooting.
I have no idea what the command was.
My first post was as 'joeyd' because I had a password problem using 'd1l2w3'.