PANIX for PC-AT uses Japanese keycodes standardized by DICOP(Desktop UNIX for Intel Cooperative Promotion Group) in Japan. Therefore keycode confliction occurs with 106 Japanese keyboard in XFree86. To avoid it, specify the keyword "panix106" in XF86Config like this:
  Section "Keyboard"
    Protocol    "Standard"
    Autorepeat  500 5
    XkbModel    "jp106"
    XkbLayout   "jp"
    panix106
  EndSection