[Plugin: Similar Posts] Code in Input Causes Problem

You can see in this snapshot:
http://i25.tinypic.com/30tga5z.jpg

It says “Text and codes between items:” so I put an image tag but the image tag has caused a problem probably from the quotation marks. I don’t know how to remove it, I can’t find it in my database.

Please and thank you for any help.
Andrew

http://wordpress.org/extend/plugins/similar-posts/