Notice: Undefined offset: 0

Hi Guys.
I have installed plugin (ver. 1.7.8) and I activated it, but I see on my website text.

Notice: Undefined offset: 0 in /…./plugins/only-tweet-like-share-and-google-1/tweet-like-plusone.php on line 229

What should I do now?

I will be grateful for help.

Best,
Peter

https://ww.wp.xz.cn/plugins/only-tweet-like-share-and-google-1/