Imports System
Imports System.IO
 
Module SplitFilenameCfg
    Public Function SplitFNtoDirectory(ByVal substring As String)
        Dim vInput As String = Nothing
        Dim overwrite As Boolean = True
        Dim firstPath As String = "C:\Test\"
        Dim success As Boolean
 
        Dim splitString() As String = substring.Split(";")
        For i As Integer = 0 To splitString.Length - 2
            Dim splitString1 As String = splitString(i)
            Dim splitString2() As String = splitString1.Split("_")
            Dim sourceFile2 As String = "C:\Test\SubTest\" + splitString1 + _
              ".usr"
            Dim subDirectories As String = splitString2(0) + "\" _
                                           + splitString2(1) + "\" + _
                                           splitString2(2)
            Dim mainPath As String = Path.Combine(firstPath, subDirectories)
            My.Computer.FileSystem.CreateDirectory(mainPath)
            Dim targetPath2 As String = mainPath + "\" + splitString1 + ".usr"
            If File.Exists(sourceFile2) Then
                File.Copy(sourceFile2, targetPath2, overwrite)
            End If
 
            'If FileCompare(targetPath2, sourceFile2) Then
            '    File.Delete(sourceFile2)
            'End If
        Next i
 
    End Function
 
End Module

Dim sourceFile2 As String = "C:\Test\SubTest\" + splitString1 + ".usr"
und 
Dim targetPath2 As String = mainPath + "\" + splitString1 + ".usr"

Dim targetPath2 As String = mainPath + "\" + splitString1 + ".usr" Or ".cfg"
oder
Dim targetPath2 As String = String.Concat(mainPath, "\", splitString1, (".usr" _
  Or ".cfg"))