There is a problem in ArtRage 2.5.16 that will most likely prevent it operating correctly under an install of Mac OSX Leopard (10.5). Specific crashes occur when checking for updates, exporting files, and may also occur in a couple of other places where file dialogues are used.
A workaround exists for the Check For Updates crash, which can occur on startup (read this thread http://www2.ambientdesign.com/forums...pic.php?t=9419 ).
We have fixed the problem internally and are testing the new version at the moment, we hope to have the fix published this week. Thanks for bearing with us!