That does sound frustrating dealing with that new tech, abigailabear. I am not sure what the error messages you got during reinstallation mean. Is the Reader Library software working ok? The uninstall / reinstall process on the Mac is not very intuitive, and people often have problems. I just reinstalled mine last month. I followed Post #5 in this thread link.
https://www.mobileread.com/forums/showthread.php?t=78921
Also, I followed the instructions to change Language to US (Computer). You can do this under System Preferences > International > Language on 10.5. If you are using 10.6, then I think it is in a different path. I would also try this suggesion. Some people have reported that it fixed their issues with Sony software just to change the language setting on their Mac.