googlebot creating and indexing non-existent pages - how to correct it

urgent help required - possible duplicate penalty applying

[elaineb]

googlebot has taken 2 of my pages eg
redwidgets.shtm and bluewidgets.shtml and proceeded to add all the rest of my pages onto the end of them eg
redwidgets.shtml/greenwidgets.shtml
and
bluewidgets.shtml/greenwidgets.shtml

so in effect Google now has 3 pages exactly the same in its index - 2 being non existent!

Has anyone any idea why it is doing this and how can I stop it - quickly.

and also how do I remove the offending pages as I have no control over them - they've been made up by Google and only appear in their index when using the site:www.mydomain.co.uk - when clicked on the original page loads but without any of the applied stylesheets.

any help or advice greatly appreciated.