How do I 'debug' a script when the message appears.?

Don't bother. That message is only helpful if you're an expert, and by asking this questions it's clear you aren't :)

Seriously, the message is mostly intended for the developer, so a user getting it is unfortunate because something happened that shouldn't have happened.

If you happen to personally know the developer of the program, and you're using the current version, contact them. In all other cases, move on.

Assuming you are using Internet Explorer as a web browser (eg:IE10 or IE11) Go to:

Tools

Internet Options

Advanced tab

Scroll down to Browsing

Tickmark to Disable Script Debugging

Click Apply

Click OK

Close all browser windows then reopen to ensure the changes to the setting stick

If you are using another web browser other than IE, indicate as such and someone can help you out.

Without even knowing what the message says, there is no way we can even begin to assist you. Besides, you admit that you're just a user, and without programming skills, it might just frustrate you trying to do something that an expert usually takes care of. It would be like if you tried to repair the engine in your car if all you do is drive. Good luck.

its talking about JavaScript and you need to have the Java Console enabled to see what code is going wrong. but really you are unlikely to understand what to do if you didnt even know that.