I also have the exact same Problem:
Warning: in_array() [function.in-array]: Wrong datatype for second argument in /var/www/wp-content/plugins/adminimize/adminimize.php on line 801
And I want to use the plugin in a productive environment, means a system sold to a client, so I need to remove the error somehow or chacnge the plugin.
Are there any solutions that I could apply instantly? Somewhere else in the forum ( http://wordpress.org/support/topic/adminimize-died-invalid-argument-supplied-for-foreach?replies=2 ) I read downgrading works. Is this a recommended solution? When can we expect a fix?
Regards and thanks in advance for a quick reply.