Banners,parallax, and other home page issues

Hi
I wonder if anyone can help.
All was working fine until I noticed on the home page that the site is having problems with the banners/parallax modules.
I get the following message and a few similar ones:

Undefined index: description in <b>/home/tubs4hire/public_html/catalog/view/theme/theme501/template/module/banner.tpl

I tried changing the theme but get the same problem. Can anyone help?

Many thanks
Simon