Using version 1.2 of the plugin, I had one user get PHP notices on his Windows server re line 154 of the plugin's php file:
( ( isset( $_SERVER['HTTPS'] ) and $_SERVER['https'] !='' and $_SERVER['HTTPS'] != 'off' )
It said the index 'https' was not defined, so I edited the code to this (in CAPS):
( ( isset( $_SERVER['HTTPS'] ) and $_SERVER['HTTPS'] !='' and $_SERVER['HTTPS'] != 'off' )
I don't think that has anything to do with the server -- PHP array indexes are case sensitive.