Runtime Error 9 with VBComponents and Dir()

Hello,
I am trying to get VBA to import a folder of .bas files into the PERSONAL.xlsb workbook upon Excel startup to ensure that users always have the most updated macros. Two lines of mine are throwing Runtime Error 9, and after playing around a bit I think it's either because I'm using Dir or there's something wrong with this line: *If IsNull(TargetWB.VBProject.VBComponents(fileNameNoExt)) = True Then Is Nothing Then*, but I'm not sure it that's what's wrong or how to fix it. (When I substitute an existing module name in quotes (no extension) for fileNameNoExt, there is no error in the AutoUpdateBasFiles sub, only in the DeleteVBComponent Sub. When I substitute a non-existent module name in quotes (no extension) for fileNameNoExt, it throws Runtime Error 9 again.) I am a novice with VBA. Any help or ideas would be appreciated.

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Sub DeleteVBComponent(ByVal wb As Workbook, ByVal CompName As String)

'Delete the component
wb.VBProject.VBComponents.Remove wb.VBProject.VBComponents(CompName)   '***THIS LINE THROWS RUNTIME ERROR 9***

End Sub


Sub AutoUpdateBasFiles()

'Automate import of all other modules
    
    Dim userID As String
    userID = Environ("UserName")
    Dim destPath As String
    destPath = "C:\Users" & userID & "\AppData\Roaming\Microsoft\Excel\XLSTART"
    Dim sourcePath As String
    sourcePath = "C:\File Path"   '**FilePath removed for the purpose of this post

    'Loop through all files in a folder
    Dim fileName As Variant
    fileName = Dir(sourcePath)
    Dim TargetWB As Workbook
    Set TargetWB = Workbooks("PERSONAL.xlsb")
    Dim fileNameNoExt As String

    While IsNull(fileName) = False
        fileNameNoExt = Left(fileName, InStrRev(fileName, ".") - 1)
        If IsNull(TargetWB.VBProject.VBComponents(fileNameNoExt)) = True Then 'Check for existence of module '***THIS LINE THROWS RUNTIME ERROR 9***
            Else
            Call DeleteVBComponent(Workbooks("PERSONAL.xlsb"), fileNameNoExt) 'Delete existing module before importing the new one of the same name
        End If

        TargetWB.VBProject.VBComponents.Import (sourcePath & fileName) 'Import the new module
        
        'Set the fileName to the next file
        fileName = Dir()
    Wend

    'Save the workbook
    Workbooks("PERSONAL.xlsb").Save

End Sub


Private Sub Auto_Open() 
    Call AutoUpdateBasFiles
End Sub