Please make sure that you have enough disk space left in your harddrive. Also can you try opening files of smaller file size. Probably something in few 100 Kbs
I have 600GB of space left still, so it's probably not that, and all the files I need to open are typically around 1MB
Go to your username>library>preferences and delete:
Adobe Photoshop Elements 10 settings
Adobe Photoshop Elements 10 paths
In 10.7 and 10.8 this library is hidden. To see it, option click the Go menu in Finder and it will appear below the little house for your user account. In those versions of OS X it's also not a bad idea to go to the Saved Application States folder while you're in the library and delete any states for PSE.