HTML Validation Constant Errors

I’m in an HTML and I don’t understand why I ‘m getting the error messages that I got. I believe I have written the HTML correctly. Can you help me?

http://courseweb.lis.illinois.edu/~booker1/lab8.html <—This is my homework link

I currently use TextPad to write my HTML if that helps.

Thanks,
Liza

NOTE: Whenever possible, give the address of the document you were checking.