Problems with Photoshop Elements 6

I have been having a problems with PE 6 crashing while making changes to images. It does not always save JPEG's correctly so when I try to open them I get a message that says there is an invalid or unknown JPEG marker. Sometimes when I save an image instead of giving me a small preview icon of the image, the icon it gives is the JPEG icon. Clicking on the JPEG icon sometimes it changes to the preview icon, sometimes not. I used to able to open images off a disc they had been burned to but can't do that any longer.
I have heard that there is a problem with PE6 and MAC's. I'm running OSX Leopard 10.7 on an iMAC.
Can anyone shed light on this. Have there been known problems between MACs and PE6? If so, what can be done to fix them?
Thanks
Bob