The only errors in Begin.vi that I see is PWM 1 is used twice.
Usually, an error like the one you are describing means the error out was deleted or the terminal was moved.
You can try clicking on the broken arrow for more information, but you probably already see all there is to see.
- Open Robot Main and there should be a broken arrow on the top menu bar on the left.
- Click on it and a list of errors should appear.
- Click on an error and it will take you to what it thinks is wrong.
If you want to attach both the Begin.vi and the Robot Main.vi we could inspect them and probably be more helpful.