Issue with word limit plus

I’ve had a site that has been live for a few days:

http://www.ourrabbijesus.com/index.php

Today I went to it using firefox and got this message at the top of the page:

Notice: Undefined offset: 20 in /home/ourrab5/public_html/orjcp/plugins/pi.word_limit_plus.php on line 70

Not being a php guy I have no idea what this means. As I said I don’t recall seeing this error before today. Here is the line of code in the word limit plus file:

{
            $str .= $word[$i]." ";
        }

Any help would be appreciated.