[Plugin: Admin Customization] Multiple warnings on dashboard after activation

Hello,
Hi,
I’ve tried your plugin (admin customization v1.2) on a test multisite with subfolders (wordpress 3.1) of mine.
As advised immediately after activation I visited the dashboard.

BUT,
on the top of the screen I got multiple warnings with the message:

Warning: in_array() [function.in-array]: Wrong datatype for second argument in …/wp-content/plugins/admin-customization/core.php on line 159

7 times to be exact. I got the same message even after deactivating a couple plugins I had active.
The message did not show up again once I saved the settings.
Thank you in advance

https://www.ads-software.com/extend/plugins/admin-customization/