I don't quite see the need for the loop and counter using your example; however, the code below solves the immediate problem.
    If WorksheetFunction.IsText(List(listpos, firstcolumn)) Then
        nonzerotext = List(listpos, firstcolumn)
    Else
        nonzerotext = "no text in range " & List.Address(0, 0)
    End If
Your original code did not work with the example because you had an empty cell in the range but your counter is not adjusted to account for it so that after that cell the count is off by one...