problemi nell'installazione di estensioni

[caravaggio]

ho installato J 1.0.13 e tutto è sembrato filare liscio. mi capita pero che installando componenti o plugins si verifichino errori. le estensioni funzionano ma nella pagina di back end o front end trovo queste tipologie di errori:

com_eweather:
back-end
Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/administrator/components/com_eweather/admin.eweather.php on line 17

com_seyret
front end
Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 1668

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 268

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 269

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 481

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 481

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 481

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 481

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 481

Notice: Trying to get property of non-object in /var/www/vhost/sierraeye.net/home/html/components/com_seyret/seyret.php on line 481

back-end
Notice: Undefined variable: keys in /var/www/vhost/sierraeye.net/home/html/administrator/components/com_seyret/admin.seyret.php on line 2786

Notice: Undefined variable: keys in /var/www/vhost/sierraeye.net/home/html/administrator/components/com_seyret/admin.seyret.php on line 2787

Notice: Undefined variable: keys in /var/www/vhost/sierraeye.net/home/html/administrator/components/com_seyret/admin.seyret.php on line 2788

mambot adsense
front end
Notice: Undefined variable: channel in /var/www/vhost/sierraeye.net/home/html/mambots/content/bot_adsense.php on line 167

Notice: Undefined offset: 0 in /var/www/vhost/sierraeye.net/home/html/mambots/content/bot_adsense.php on line 223

Immagino che installando altre estensioni otterrei problemi simili.
sapete da cosa dipende e come risolvere il problema?

il sito è www.sierraeye.net