Run-time errpor 52 Bad file name or number

Hello. I'm a vb script newbie. I am debugging a VB script Excel Macro. The Macro is suppose to create a PDF once a button is selected. I am getting a runtime error 52. Bad file name or number. Below is the Function. When I select Debug, the following line is highlighted If Dir(Fname) <> "" Then
ANy ideas?

Thank you

Function RDB_Create_PDF(Myvar As Object, FixedFilePathName As String, _
OverwriteIfFileExist As Boolean, OpenPDFAfterPublish As Boolean) As String
Dim FileFormatstr As String
Dim Fname As Variant

'Test If the Microsoft Add-in is installed
If Dir(Environ("commonprogramfiles") & "\Microsoft Shared\OFFICE" _
& Format(Val(Application.Version), "00") & "\EXP_PDF.DLL") <> "" Then

If FixedFilePathName = "" Then
'Open the GetSaveAsFilename dialog to enter a file name for the pdf
FileFormatstr = "PDF Files (*.pdf), *.pdf"
Fname = Application.GetSaveAsFilename("", filefilter:=FileFormatstr, _
Title:="Create PDF")

'If you cancel this dialog Exit the function
If Fname = False Then Exit Function
Else
Fname = FixedFilePathName
End If

'If OverwriteIfFileExist = False we test if the PDF
'already exist in the folder and Exit the function if that is True
If OverwriteIfFileExist = False Then
If Dir(Fname) <> "" Then Exit Function
End If

'Now the file name is correct we Publish to PDF
On Error Resume Next
Myvar.ExportAsFixedFormat _
Type:=xlTypePDF, _
FileName:=Fname, _
Quality:=xlQualityStandard, _
IncludeDocProperties:=True, _
IgnorePrintAreas:=False, _
OpenAfterPublish:=OpenPDFAfterPublish
On Error GoTo 0

'If Publish is Ok the function will return the file name
If Dir(Fname) <> "" Then[/B] RDB_Create_PDF = Fname
End If
End Function