Can't create CD disc image copy in MF4

[alancross]

*** XP Home; Plextor PX-716A CD/DVD ***
I guess it's probably me, but I can't fathom! I'm trying to create a backup (image) CD for some software that is to be (legitimately!) shared. This is what I'm doing:
Insert source disc (and cancel autoplay)
Start MF4; choose 'copy or fit disc'; chooese 'disc to disc copy'
Set source as Plextor; set destination as 'disc image file'
Hit Copy; select folder and filename; choose ISO format
Get message 'Operation completed successfully'
Close MF4; swap source disc for blank CD
Open MF4; choose 'burn image to disc'
Hit 'Copy'; get message 'Intialising disc for recording, Recording at 48X'
Then: "A GENERIC ERROR HAS OCCURRED. MAKE SURE THE BURNER IS READY AND TRY AGAIN'.
The burner is then not available as a Destination, is not visible in Windows Explorer, and I can't eject the disc. Have to re-boot to retrieve disc.
Can anyone help? I have the problem regardless of format I choose for the image file, and regardless of whether I source from this software CD or from a data CD I have cut myself.
Thanks in anticipation!