I am having a problem with the forms on the sites.Help?

I am having a problem with the forms on the sites.Help?

Any suggestions why I can't add any type of form to my site. It only turns up with "Error in creating form, Try again".

And a bonus question. Why can't I delete and old site from "Manage sites"? I have one that hasn't got a name, which I can't delete for some odd reason.