Not sure how you were trying to make a copy of the workbench, but the workbench disk is not copy protected, so any disk copier should be able to make a duplicate, without any trouble. You might want to try a copier like XCopy, or one of the freely available disk copiers with validate function, though, so you can see if you get any read/write errors.
The Amiga should use double sided, double density disks (2SDD) not high density (HD). Writing to a HD disk may or may not work, and the written data may or may not corrupt itself quickly after write. I've used HD disks in a pinch and had them work for short periods of time, but I've also heard from a lot of people who have tried it and had them fail. Personally, I stick to 2SDD for anything I plan to actually use for more than 10 minutes.
Arkanoid 1 is available legally and freely from the excellent
back-2-roots website. :-)
