Certain links from an external application are failing to open in Firefox (but open fine when IE is the default browser instead). This problem was occurring in the 3-point-something version I was previously running, as well as in the 6.0 I'm running now. If Firefox is not running when I click the external link I receive an error dialog "There was a problem sending the command to the program." Otherwise, it fails silently. The links are being provided by an RSS feed in an external reader. Recently the feed changed the formatting for their URLs. The links that work look like: http://catalog.spl.org/ipac20/ipac.jsp?profile=dial&full=3100001~!2725646~!6 The links that do not work look like: http://catalog.spl.org?profile=dial&view=items&uri=full=3100001~!2732159~!2&term="Science fiction." I'm not clear on whether the problem is the lack of a / between the hostname & the query string (an RFC violation, but one that Firefox handles if the URL is just pasted into the address box) or something else. I have also contacted the maintainers of the RSS feed, but would like some more input onto whether this is actually the problem (and, if there's a way I can fix it on my end, in case there's not speedy change on the part of the folks generating the feed).