'guid' is null or not an object- appears to be a css error from googling it

Hi all,
I get this js error which appears to be a hover error as far as I can gather from googling it, but I am stuck as to why it is throwing this error:

Message: ‘guid’ is null or not an object
Line: 25
Char: 10976
Code: 0
URI: http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js



I deactivated a plugin and now the error has gone.