调用过程提示：编译错误！类型不匹配！

写了点调用过程的代码，试运行的时候提示：编译错误！类型不匹配！
代码如下（无关代码省略）：
Private Sub Command1_Click()
Open Text1.Text For Random As #1 Len = 1
Dim d As String * 1
'On Error GoTo ddd
Do Until EOF(1)
Get #1, , d '此处实际读出为“d”
Select Case d
Case "d"
List1.AddItem sub_d()
........
End Select
Loop
Close #1
ddd:
End Sub

Private Function sub_d()
Dim a As String * 1
Dim pp As String
pp = "{"
Do
Get #1, , a '此处实际读出为“8”
Select Case a
........
Case "1", "2", "3", "4", "5", "6", "7", "8", "9", "0"
pp = pp & sub_no(a)
........
End Select
Loop
pp = pp & "}"
sub_l = pp
End Function

Private Function sub_no(ByVal sub_no_no As String) '提示此行编译问题，类型不匹配！
'单步跟踪问题依旧，sub_no过程
'代码根本未执行。故不怀疑sub_no
'过程代码有问题
Dim sub_no_a(0 To 100) As String * 1
Dim a As Long

Dim n As Integer
For n = 0 To 100
Get #1, , sub_no_a(n)
If Val(sub_no_a(n)) = 0 Then
If sub_no_a = 0 Then
Else
Exit For
End If
End If
Next n
Dim p As Integer
p = 0
For m = n - 1 To 0
a = a + Val(sub_no_a(p)) * 10 ^ m

p = p + 1
Next m
a = a + Val(sub_no_no) * 10 ^ n
Dim dd As String
dd = sub_no_a(n)
For d = 1 To a - 1
Get #1, , s
dd = dd & s
Next d
sub_no = dd
End Function

怀疑另有玄机，另写一测试代码，竟毫无任何问题通过
测试代码：
Private Sub Command1_Click()
Dim a As String * 1
a = "1"
Label1.Caption = sub_a(a) '执行后label1显示结果为2
End Sub

Private Function sub_a(ByVal sub_a_a As String)
Dim b As Integer
b = Val(sub_a_a)
b = b + 1
sub_a = b
End Function
将vb关掉再重新启动，问题依旧。遂迷！
请教高人！不盛感激！