More information would be helpful.
OS 9 handles disk images natively.

Try dropping it on Stuffit Expander, that usually does the trick. It sounds like you have deeper issues or the .img file is wanky, Rebuild the Desktop, Zap the PRAM.

Reinstall Disk Copy:

http://www.pure-mac.com/appud.html ...

I'm so pleased you have picked up this wonderful resource.
I haven't had much time to read all of what was included with the transfer. I'm hoping the programs/utilities database was included, as this has been, in the past, a real helpful site for those of us with these wonderful old Operating ...