VBA Mid() и ошибка Invalid procedure call or argument (Error 5) Опции

[Litkevich Yuriy]

Связался тут с очередным уродцем, коих плодит мелкософт.
Получаю во время выполнения ошибку "Invalid procedure call or argument (Error 5)"
Часть кода:

    Dim pos As Long
    Dim cnt As Long
    Dim tmp As String
    Dim origName As String
'...
tmp = Mid(origName, pos + cnt, 1)

Описание функции Mid:

Раскрывающийся текст

Returns a Variant (String) containing a specified number of characters from a string.

Syntax

Mid(string, start[, length])

The Mid function syntax has these named arguments:

Part Description
string - Required. String expression from which characters are returned. If string contains Null, Null is returned.
start - Required; Long. Character position in string at which the part to be taken begins. If start is greater than the number of characters in string, Mid returns a zero-length string ("").
length - Optional; Variant (Long). Number of characters to return. If omitted or if there are fewer than length characters in the text (including the character at start), all characters from the start position to the end of the string are returned.

не пойму, что неверно

Не знаю какую религию мелкософтники исповедуют, но она им не позволяет нормальные сообщения об ошибках формировать.