Dynamic dropdownlist error

[shahDeveloper]

i have created a number of combo boxes according to my need.no i want to save the changes when any one click update button,but here the control did not find by findcontrol function.
Dim i, j, totc As Long, FcNo As String, cmbcat As Object, fid As ArrayList
catarry = New ArrayList
catarry = CType(ViewState("catgs"), ArrayList)
totc = CLng(ViewState("totcts"))

For i = 0 To totc - 1
'for category combo box
'cmbcat = New Object
'cmbcat = CType(Me.FindControl("catpp" & catarry(i * 3 + 1)), DropDownList)
'cmbcat = CType(Me.FindControl("catpp" & catarry(i * 3 + 1)), DropDownList)
'cmbcat = CType(Me.FindControl("catpp" & catarry(i * 3 + 1)), DropDownList)
If Not CType(Me.FindControl("catpp" & catarry(i * 3 + 1)), DropDownList) Is Nothing Then
FcNo = CType(Me.FindControl("catpp" & catarry(i * 3 + 1)), DropDownList).Text
End If
StrQry = "update category set cat_order=" & FcNo & " where cat_no=" & "catpp" & catarry(i * 3 + 1)
'Now check for all forums of category
fid = New ArrayList
fid = AllFunctions.PopToarraylist("select Forum_No from Forum where cat_no=" & catarry(i * 3 + 1), 1)
For j = 0 To fid.Count - 1
cmbcat = New Object
'cmbcat = CType(FindControl("frmpp" & fid(i)), DropDownList)
'cmbcat = CType(FindControl("frmpp" & fid(i)), DropDownList)
'cmbcat = CType(FindControl("frmpp" & fid(i)), DropDownList)
If Not CType(Me.FindControl("frmpp" & fid(i)), DropDownList) Is Nothing Then
FcNo = CType(FindControl("frmpp" & fid(i)), DropDownList).Text
End If
'cmbcat.Text
StrQry = "update Forum set Forum_Order=" & FcNo & " where forum_no=" & fid(i)
AllFunctions.UpdateQry(StrQry)
Next
Next