Errand boy gets sheet (4)
I believe the answer is:
page
I believe this clue is a double definition.
'errand boy' is the first definition.
(I know that page is a type of errand boy)
'sheet' is the second definition.
(sheet of paper)
'gets' is the link.
(Other definitions for page that I've seen before include "Youth acting as a knight's attendant" , "Young attendant for part of a book" , "Leaf - young attendant" , "Attendant - this is on one!" , "contribution to book?" .)