I see extra code appended after the closing </html> tag the links to an image on the site that the Google diagnostic page mentions (imgddd.net)

• view-source:http://www.bluerose.no/

The presence of such code at that position usually indicates that the site was hacked and compromised.

It is not the Firefox browser nor Mozilla that is doing the blocking but rather Google safe browsing.

http://www.google.com/safebrowsing/diagnostic?site=http://www.bluerose.no/

What is the current listing status for bluerose.no?

   Site is listed as suspicious - visiting this web site may harm your computer.

   Part of this site was listed for suspicious activity 6 time(s) over the past 90 days.

What happened when Google visited this site?

   Of the 2 pages we tested on the site over the past 90 days, 2 page(s) resulted in malicious software being downloaded and installed without user consent. The last time Google visited this site was on 2011-08-26, and the last time suspicious content was found on this site was on 2011-08-26.

   Malicious software is hosted on 1 domain(s), including imgddd.net/.

   This site was hosted on 1 network(s) including AS34989 (SERVETHEWORLD).

Has this site acted as an intermediary resulting in further distribution of malware?

   Over the past 90 days, bluerose.no did not appear to function as an intermediary for the infection of any sites.

Has this site hosted malware?

   No, this site has not hosted malicious software over the past 90 days.

How did this happen?

   In some cases, third parties can add malicious code to legitimate sites, which would cause us to show the warning message.

Once you get the issue fixed you can then have Google check and remove. http://www.google.com/safebrowsing/report_error/