Hiding rows in a function

[Aero]

Hmm,

now it hides all the rows 1 untill 50, when all 50+ rows should be hidden...

I might have to be some more specific, this is what i do :

Function tabledim(ws As Worksheet, h As Integer, w As Integer)
    Dim i As Integer
    Dim k As Integer
    Dim n As Integer
n = Cells.SpecialCells(xlCellTypeLastCell).Row
For i = 1 To 7 * h
        Rows(i).RowHeight = 7.5
    Next i
k = 7 * h + 1
    Rows(k & ":" & n).Hidden = True
End Function

(The first 50 rows will have data later on)

EDIT: i think i'm seeing 'n' wrongly, it probably doesn't mean 'end of document' ?