Open Internet Explorer.
On the Tools menu, click Internet Options.
In the Internet Options dialog box, click Advanced.
Click to select the Disable script debugging check box.
Click to clear the Display a notification about every script error check box.
Click OK

The error is probably being thrown because there is a scripting error in your webmail.. It's not your fault except that Internet Explorer's settings are requiring all those scripting issues to be displayed.. The steps above should stop the messages from popping up constantly.

Hope this helps.