[Plugin: SubHeading] is_main_query fatal error on wp prior to 3.3

Hi, I know that one should mantein his WP always up to date, but in my case I have to wait.

I updated subheading to 1.6.6 and it was broken in my WP 3.2.1 because is_main_query doesn’t exist in that WP version.

Could that function be substituted with anything else function/s that does the same thing maybe?

http://wordpress.org/extend/plugins/subheading/