My issue with this was with the DDSitemapGen plug in by http://www.dagondesign.com/articles/sitemap-generator-plugin-for-wordpress/
I fixed this by adding "post_type" to the list on line: 881
SELECT post_title, ID, post_status, post_type, cat_ID, post_date, cat_name
and then on line: 887 I copied the line that was there created a new line below it pasted it and changed it to:
AND post_type != 'page'
Seems to have fixed the issue with this plug in I was having, so if anyone else is having the same issue and knows less about PHP than even I do here is a fix until it is updated by Dagon.
Thanks again moshu, it was you that led me to this solution. :)
Edit: I should add that this may not be an ideal solution, it just fixed the issue I was having. There may indeed be a better way.
Ben