Problem: Your first line of text on each page is too close to the header. It appears that there is single spacing between the body of the document and the header.
Cause: This is almost always caused in Word when the user manually changes the spacing to "double spaced."
Solution: Change the line spacing to "at least 28 point."
Explanation: "Double spacing" is not relative to any baseline measurement and Word is free to interpret and adjust the spacing how it chooses. By telling Word to use "at least 28 point" you are giving Word an absolute measurement relative to the 12 point font. (2 x (12 points + 2 point leading) = 28 points). Word will not adjust line spacing to be less then this measurement.