CGI:IRC doesn't use Java so that is unrelated. (I also have the JRE 6u27 console disabled in Firefox.)
As a test, I logged on with Firefox 6.0.1 and closed #landzdown.com via the X in the corner (highlighted in the attached image). Then, as suggested by Aaron, I entered /join #landzdown.com in the text input space from the Status window. I was reconnected.