Did you Compile your database?

Debug - Compile

Nope. Thanks for the tip. I'll try that when I have the chance.

Yeah, I got this on my first run. It usually means there is an error in your code which isn't being picked up. Doing as Kevin says will usually jump to where the error is - you fix it and re run compile until all clear, then you'll be good to go. Failing that, you might need to Decompile, then recompile the database (this has worked in the past for me as well). When all else fails, you can transfer everything into a new access database file but I doubt you'll Have to go that far.
Search for 'troubleshooting' and 'compile' Tech help videos - absolute essentials and worth keeping saved somewhere in case you ever get a a point like this.