Input/output error installing in Ubuntu

[nickc]

Hi all, have just joined in order to post this:

I was happily running ZD 2.0.1 (I think it was) under Ubuntu 11.04. But I was having glitches in my OS, so did a fresh install of Ubuntu, upgrading to 11.10. I had backed up the ZD folder in my home directory, and copied it back once the Ubuntu installation was complete. Now I've tried reinstalling the latest ZD and I'm getting an error message soon after the installer attempts to install the application files. Everything stops, with the message: "Installing application files...cp: reading `./app/linux/jre/lib/rt.jar': Input/output error"
I wondered if it had been a mistake to copy the ZD folder back to my home directory (don't see why, as it's just the data) so tried renaming it, then running the ZD installer again, but got the same error message. Can anyone help me out?