Found it!

 

Line 833 of include_phpuploader.php "$data=base64_decode($filedata,false);"  My environment/client combonation returns that this function only takes 1 argument and there are two supplied.  We are running PHP 5.1, which I"m guessing is out of spec as there is a call to a function "error_get_last()" which is not supported until 5.2.  I'm still not entirely sure why only two particular installations of XP triggered the issue.  Reguardless, I've removed the second argument from the decode function, wrote an error_get_last, and all is working now.

 

Thanks!