With regard to your loop, wTable is a Word Table not an Excel table, so you have to use the Word VBA command set. Thus for cells 2, 3 & 4 you cannot use 'Formula' to fill the cell as if it was an Excel cell. You need to resolve the values separately and write the results to the appropriate cell's Range.Text.

For i = 2 To intNoofRows
    wTable.Cell(i, 1).Range.Text = i - 1
    wTable.Cell(i, 2).Formula ("=Date(Year('Payoff-Zero Call'!$C$22)+i-1,Month('Payoff-Zero Call'!$C$22),Day('Payoff-Zero Call'!$C$22))")
    wTable.Cell(i, 3).Formula ("=Input!$D$5 & Round((1000000*(1+100*Input!$I$5/100)^(i-1)),2)")
    wTable.Cell(i, 4).Formula ("=ROUND((1000000*(1+100*Input!$I$5/100)^(i-1)),2)/1000000")
Next i