No Powermac can run 10.6.7. Secondly, sometimes the recent documents folder in the Users -> your name -> Documents -> Appleworks can sometimes get corrupted. Delete its contents when Appleworks is not running. That may solve the problem. IF you are running 10.6.7, apply the necessary 10.6 updates to be secure:
If that still doesn't help, please clarify what system you are running, how much free space you have, and how big is your hard disk, and the status of your backup?
As a brody has said problems can be caused by AW Recent Documents especially if there are a lot of items in there.
If clearing them does not solve the problem it would be worthwhile trashing AW preferences as a next step (Home > Library > Preferences > AppleWorks > AppleWorks 6 Preferences).
What sort of format/file size is the artwork?
How much spare space is there on your HD?