How do I stop pop-ups from javascript runtime and other errors?
"A Runtime Error has occurred" is displayed when there is a JavaScript error. You may see these errors more often with Pop-Up Blocker enabled because some web pages are trying to communicate with their blocked pop-up window.
To stop seeing these error windows, go to
Tools > Internet Options...
and click on the Advanced tab.
Under Browsing, check the box for Disable script debugging.

You will still be able to see Javascript errors by looking at the page status in the lower left corner of the browser window. When the status is "Error on page", you can click it for more info.