Hello All, I had this problem before and all I did to fix it was disabling the Java Deployment Tool Kit plugin

To do that you go to Firefox >> Addons>>Plugins you will see a box to the right that say disable

Hope this helps :)

I had the same identical problem. I found this link to be helpful.

http://www.askdavetaylor.com/why_mailto_links_not_clickable_firefox.html

This link was the foundation for finding the solution to my problem. I followed the recommendations per the article with no success. However, upon further scrutiny of the line codes.... review the following line:

network.protocol-handler.external.mailto is "True". Default setting is False. When this was changed to "True", my website link (mailto:) began to operate properly.

I hope this helps..............

In addition, you must see that your default settings in Windows are properly set