[Calibre_N00b]

So I am very new to Calibre and to Kindle itself, we are talking just a couple of hours, so I apologize in advance if the problem I am facing is very obvious and very amateur-ish.

So I tried converting a PDF formatted book into .MOBI. The conversion went not so greatly, I keep getting these at the end of each page and other times just in random places...

(This was in the acknowledgment section of the book)
Chapter = ack
Date: August 26, 2009
Time: 9:11 am

(For example this was stamped at the end of each page in chapter 1)
Chapter = c01
Date: July 8, 2009
Time: 6:35 pm

Can anyone please help me understand why I am getting these and how I can remove it please?

Again I apologize in advance if this is a very stupid question, as I said I am very very new to all this.

Thank you,