2 Problems with Dashboard Plugin and every other plugin

I have 2 major problems

1. If the WPMUDEV Dashboard Plugin is deactivated, it get this Error

[Tue Jul 02 20:53:47 2013] [warn] [client xx.xx.xxx.xxx] mod_fcgid: stderr: PHP Notice: bp_setup_current_user was called incorrectly. The current user is being initialized without using $wp->init(). Please see Debugging in WordPress for more information. (This message was added in version 1.7.) in /var/www/vhosts/domain/httpdocs/wp-includes/functions.php on line 2962, referer: http://www.domain.xx/wp-admin/plugins.php

2. Is the Dashboard activated, i get a white, blank screen on the plugins.php page in the Admin menu.

i have to reload the site 3-4 times before i see the plugins again.