seadad9903,
If you have only added books and corrected/tweaked some of the metadata (mostly correcting errors from adding the books rather than adding any new info), it might be a whole lot easier to start all over again. Sometimes dealing with dozens of minor errors, requiring dozens of regex expressions or hand-editing attempts, becomes very frustrating.
To start all over from scratch, you should create a new, empty database (use Choose library>Switch or create library>Enter a new path>Create new library). Then you could change the input formula under Configure>Import/Export>Adding Books>Regular Expression (field halfway down the dialog) and use the suggested regex from my post in
Tyrannosaurus Regex.
Read the message in that post carefully, and know that the " - " (space dash space) between elements is absolutely mandatory. If your filenames follow that format you should be fine. Anything that doesn't follow that exact format will result in input errors like you're already seeing and will need to be corrected. This might, at the very least, reduce the number of errors that need to be corrected by hand.
If you've customized your database or have entered a lot of unique metadata (say, book reviews from dozens of sites, added lots of tags, downloaded lots of covers, etc) then correcting what you've already got is the better choice.