When the xfce4-weather plugin is added to the panel in xfce-4.0.4 or xfce-4.0.5 on sparc, it will crash the panel. Will look into it as time permits. This is mostly here so that people are aware.
From our IRC discussion in #gentoo-sparc on April 21st, the method in the post http://lunar-linux.org/pipermail/xfce/2004-March/008637.html does work for me. The problem was that if you change the xfce4rc file while xfce4 is running, it will get overwritten when xfce4 is shutdown. I also get the panel crashings when you try to adjust the applet at all. If you come across more information on it, let me know. I'll try to look into it more as time permits.
Fixed in 0.3.9.1
