Here is the actual error message:
Run-time error '1004'
Method 'GetOpenFilename' of object '_Application' failed
Here is more code:
Dim fname As Variant
Dim FNUM As Long
Dim SLINE As String
Dim I As Long
Dim RW As Long
fname = Application.GetOpenFilename(filefilter:="TEXT FILES (*.TXT), *.TXT")
If fname <> False Then
FNUM = FreeFile()
Open fname For Input As #FNUM
Do While Not EOF(FNUM)
Line Input #FNUM, SLINE
RW = RW + 1
For I = 1 To Len(SLINE)
Cells(RW, I).Value = Mid(SLINE, I, 1)
Next
Loop