A07 doesn't exist in Worksheets("PERT CHART").Range("H1:BM150") so rngX is set to Nothing
Capture.JPG
That causes
Cells(i, 4) = rngX.Offset(0, 3).Address
to fail
This skips that line if rngX is Nothing (which works), but you may need to investigate why A07 is not in H1:BM150
Option Explicit
Sub FindText2()
Dim rngX As Range
Dim rngX2 As Range
Dim inarr As Range
Dim inarr2 As Range
Dim i As Integer
Set rngX = Worksheets("PERT CHART").Range("H1:BM150")
Set rngX2 = Worksheets("PERT CHART").Range("H1:BM150")
Set inarr = Range("A1:A50")
Set inarr2 = Range("A1:A50")
For i = 3 To 50
If inarr(i, 1) <> "" Then
Set rngX = Worksheets("PERT CHART").Range("H1:BM150").find(Cells(i, 1), lookat:=xlPart)
If Not rngX Is Nothing Then
Cells(i, 4) = rngX.Offset(0, 3).Address
End If
End If
Next I
inarr2 = Range("A1:A50")
For i = 3 To 50
If inarr2(i, 1) <> "" Then
Set rngX2 = Worksheets("PERT CHART").Range("H1:BM150").find(Cells(i, 5), lookat:=xlPart)
Cells(i, 6) = rngX.Offset(0, 0).Address
End If
Next I
End Sub