Why would I get "The server's certificate chain is incomplete, and the signer(s) are not registered. Accept?" from an official governmental site?

This happens when I try to list the available jobs.

>I enjoyed your post immensely. It also coincided with an update from the DOD who has just launched a new website that is soliciting jobs in order to Support Our Friends in Iraq and Afghanistan.
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>For an interesting read check out the site
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>http://cpolsdev.belvoir.army.mil/sofia
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>Here is the email from the DOD:
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>I had a few good chuckles ... especially when I read about the computer position, starting at $35,519 ... all that cash and I still get the perk of working in beautiful/scenic Iraq or Afghanistan. I wonder, do they pay a death premium? Maybe someone should tell the Apple blogger about this employment opportunity.
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>No. 805-03
>Immediate Release
>Oct 30, 2003
>(703)697-5131(media)
>(703)428-0711(public/industry)
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>Supporting Our Friends In Iraq and Afghanistan (SOFIA) Web Site Opens
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>The Department of Defense announced today that it has established an Internet site for recruiting temporary contract federal civilian workers to assist in rebuilding the nations of Iraq and Afghanistan
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>Supporting Our Friends in Iraq and Afghanistan (SOFIA) is a Department
>of Defense program that seeks to hire motivated civilian employees to help the fledgling Iraqi and Afghani governments in their quest to become full-fledged democracies.
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>SOFIA's web site is located at: http://cpolsdev.belvoir.army.mil/sofia
>[http://cpolsdev.belvoir.army.mil/sofia]. Job skills being sought are numerous and across the spectrum, including civil engineering, banking, agriculture, education, communications and security. Interested applicants should search under the 'Available Opportunities' section for current job vacancies in Iraq and Afghanistan.
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>Individuals will be hired by the department through the U.S. Army, which is the executive agent, for a 12-month period with the option to extend. Applicants do not have to be current or past federal employees.
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>Prospective applicants must be willing to live under field conditions.
>Foreign language aptitude and prior military experience are helpful but are not required.