It requirs for Flash Player to be installed onto your PC before viewing the board. I don't think Flash Player has a Japanese specific version. Just now I uninstalled my Flash Player from my PC and installed it through the following page; http://www.macromedia.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash&P5_Language=English
Then the page showed up without fail again. My PC uses XP and IE6.