Richard,

Try something like this;

WITH thisform.ws_pageframe.page5
   thisform.ws_pageframe.page4.txtProj_Mhi.value = ;
      .mhi_amt1.Value + .mhi_amt2.Value + .mhi_amt3.Value + ;
      .mhi_amt4.Value + .mhi_amt5.Value
ENDWITH

It apeears that mhi_amt1 is a textbox and you want the value from it. I also assume that mhi_amt# are all textboxes.