There's a bug in clause:

Public Function ImportData(ByVal sSql As String, ByVal Filename As String, Optional ByVal Delimiter As String = ";", Optional ByVal Disconnect As Boolean = False) As Boolean

It should be:

Public Function ImportData(ByVal sSql As String, ByVal Filename As String, Optional ByVal Disconnect As Boolean = False) As Boolean

Format in data file should be then: 100,'a','b',8 (separated by comma, not semicolon).

Sorry about that forgotten part in the code.

BR
Nakkimake