Line numbers could be written down the left side of the Scripts dialog so that the user isn't forced to use the Goto Line button to determine what line number is causing the error in the script. They can simply browse to it. Also, line numbers on the side is much easier to see than it is at the bottom shown with the character number.
Macromedia Dreamweaver in it's CODE view is a good example of printing line numbers down the side of the dialog.