I believe StudioPress removed the 5 columns, I just can’t remember why exactly.
Technically you could just use the 4 columns, and then add an extra column…then go into your css and copy the four column code, relabel it as fifth, then adjust the width of it so it extends and shows 5 columns in a row. If you do this, send me a link and I can help you come up with a width that works.