Error System.ArgumentException: Illegal Characters In Path

I am getting below error, when passing the path which has space between the folder name.

"System.ArgumentException: Illegal characters in path"

I have declared the the path in the variable like below:

Dim sFilename As String = "C:\Test\Windows Service\Schedule.xml"

or I have tried like this as well but same error I am getting.

Dim sSFilename As String = """C:\Test\Windows Service\Schedule.xml"""

and passing this file name to the below code:

Dim docDataSet As New DataSet
Dim docReader As New XmlDocument
Dim xnl As XmlNodeList

[code]....