Jar Launcher not wanting to open?

Hello. Today I tried opening a Jar file that you can open and has a GUI. However, I got an error: ' The application "Jar Launcher.app" can't be opened. -1712'

This is really surprising as I could open a Jar file yesterday, but now I can't. I also went to the CoreServices folder in the Library, which contains Jar Launcher. I tried to open it but it showed the same error. Can anyone help me?

~MacBookIsCool