Subscript out of range (Error 9)

Subscript out of range (Error 9)

SourceBook = ActiveWorkbook.Name
SourceSheet = Workbooks(SourceBook).Worksheets(2).Name
If Workbooks(SourceBook).Sheets(SourceSheet).Range("B10") = "SM" Then
Workbooks(SourceBook).Worksheets(SourceSheet).Range("D11:D3000,K11:K3000,N11:AC3000,CX11:CX3000,DD11:DD3000").Select
Selection.Copy
When i type code above, i am getting result. But later, when i type code,
ElseIf Workbooks(SourceWorkbook).Sheets(SourceSheet).Range("B1") =
"Status" Then MsgBox ("okay....")
it shows "Subscript out of range (Error 9)".
can you help?