I have Xfce 4.0.6 in Debian Sid. And I have weather plugin v 0.3.9-1 installed and loaded by default in panel. When I login into xfce and internet is not avaliable then weather plugin not allow panel to load (I think) and the panel does not shown. I think that it should be solved: perhaps it's a bug of weather plugin for searching all the time internet connection, but it's also a bug of panel: panel have not to allow that a plugin crashes it, I think Thank you in advance, Xan.
Additional information: My debian packages: dpkg -l "xfce*" Desitjat=Desconegut(u)/Instal
you need to report this to the author of the weather plugin.