Using the default File Manager on my phone, I navigated my "data" file from ClockWork, which I used to back up my phone prior to Liberty. However, my data is called "data.img" and I am unable to open it. Is this why I need root explorer to be able to open these types of files or did my backup not work correctly or something?
It looks like the backup is in the form of a disc image. There may be a way to extract files from the data.img file but if there is, I don't know it. The only solution I can think of is to make a new backup, restore the old backup, copy the highscores.lua file to your SD card, restore the new backup, and then use Root Explorer to copy the highscores.lua file from your SD card to the appropriate folder.
I know, I know, that's a pain. If anyone else has an easier solution for pulling files out of Android .IMG files, I'm certainly interested in knowing it.
(Note: On retrospect, the OI File Manager that comes with Liberty may or may not be able to write to your /data folder. I know that it can't write to the /system folder, which is why I removed the file manager from my phone awhile ago and use Root Explorer instead. But you should try it and see; if it works, that would save you a few bucks from not having to buy Root Explorer.)
(Note #2: Alternatively, if the OI File Manager refuses to write to the /data folder, you can still save yourself a few bucks by creating an update.zip file that copies the highscores.lua file into the appropriate folder. Let me know if you want to pursue this route and need help. Try using the Liberty File Manager first, though.)