List of urls that won't work

For some reason, again, some urls simply won't show up in my Firefox browser window. Just for fun, I'm going to try and compile a list of urls that don't load. Hopefully, there'll be someone who will be able to determine what the common denominator is for all the sites.

The problem: Every time this happens I have to start internet explorer and repaste the url into the ie url bar ... which is a pain, mostly because you have now navigate using two browser apps and ie doesn't have 'tabbed browsing'.

http://www.whatsonwinnipeg.com

FireFox won't load certain pages

Problems associated with FireFox 1.5.0.4 that I don't think I had before the upgrade. Both pages shown below successfully load using Microsoft Internet Explorer (ie) . If ie had tabbed pages, I'd be ok using it.

Here are two examples of pages that won't load. It's apparently a random event. Any ideas on getting to the bottom of this issue will be appreciated.

jeff@jeffchapman.com

Example One. Trying to study the Xplane company web site.
Attempted url: http://www.xplane.com
Tab title: "(Untitled)"

Example two. Trying to log into my web mail client from network solutions.
Attempted URL: http://mail.jeffchapman.com
Tab Title: "Network Solutions Webmail"