Error Activating Plugins

I recently installed WP 2.0.3. I have 2 copies running, one on a local machine, and one in a hosted environment. Today, all of my plugins started showing as deactivated, and I receive the following when attempting to activate any plugin (such as Hello Dolly):


Warning: in_array() [function.in-array]: Wrong datatype for second argument in pathtomyrootwp-adminplugins.php on line 100


The error appears directly above the plugin summary table, and appears once for every installed plugin.

I have deleted every file in the hosted environment and re-uploaded from a fresh copy of thw WP 2.0.3 zip and the error is still present.

I have also spent, literally, hours trying to trouble-shoot the issue myself by looking through the forums here and any information I could find through google.

I would appreciate any help.

Environmenr: windows, mysql 5.0.19-nt, PHP 5.1.1