No, it isn't the site, it is your computer. Specifically, the little java applet running to the right of the bar. As the name suggests, it is a basic "runtime error." VERY common.
My fix? Stop using IE as you should have done so years ago. Firefox has always been the choice of nerds and is also free. IE is a dinosaur, bloatware and runs slower then hell. Use Firefox. Free, faster, more secure and able to customize 1000x more than IE. Download, install, import your bookmarks and, voilá, problem solved.
This pop-up has been pissing me off for the past week. Everytime I get to JP.com and post/backread, after a few minutes, I get this message and I have to close the page and start over!!!! I don't know if it's my computer's problem or the website's...and I'm REALLY hoping this isn't the beginning of the end for my laptop.