Cannot Open Javascript in MonoDevelop

Hello, I am new to Unity3D. I have this little (actually big) problem when I open a Javascript. I cannot use MonoDevelop for JS. Whenever I double click the script, an error pops up, which reads:

Windows Script Host

Script: E:\Unity\Project1\Assets\CartoonSoldier\Scripts\guns\dustCloud.js

Line: 1

Char: 10

Error: Expected ‘;’

Code: 800A03EC

Source: Microsoft JScript compilation error

Any help (as long as it helps my problem) is appreciated.

Try open this script by “Show in Explorer” and with some text editor. Copy this script and create new “dustCloud.js” and paste this copy.