Bugs (rubriques e plugin)

I installed SPIP 1.9.2a with two plugin (Spip meteo SPIP-Surcharges). Every
time I modify a rubrique, when I confirm with "save" button, the rederict is
?exec=admin_plugin and not ?exec=naviguer&id_rubrique=xx. Can you help me to
find the way to correct ?

And more, if I try to install stable plugins (like "Gestion documents") on
the remote server, I get a blank page on the whole site. Is there a
configuration error on the server? Is it about CHMOD?

Thanks very much for your help,

Marina