Presentations.Open Method failed for MS PowerPoint 15.0 Object Library - vba

Question

I am calling VBA code from an Excel spreadsheet to open an existing PowerPoint file via the Presentations.Open method. In my environment I developed via Early Binding using the MS PowerPoint 14.0 Object Library and the codes run without a problem.
However, when the script was called in another machine that runs MS Office 2013 (i.e. MS PowerPoint 15.0 Object Library), a Run-time error pops up
Method 'Open' of object 'Presentations' failed
Is the Presentations.Open method deprecated in PPT 15.0 Object library? I tried searching Internet but couldn't find documentation on the change.
I also attempted to use Late Binding to see if it works, but received the same error.
Please find below the code snipnets I used (early + late binding).
Thank you very much for the help.
Early Binding Code Snipnet
Sub EarlyBinding()
Dim ws As Worksheet
Set ws = ThisWorkbook.Worksheets("Sheet1")
Dim PowerpointApp As PowerPoint.Application
Dim myPresentation As PowerPoint.Presentation
Set PowerpointApp = New PowerPoint.Application
PowerpointApp.Visible = True
Dim myPath As String
myPath = ws.Range("wk_dir").Value & "\" & ws.Range("ppt_name").Value
Set myPresentation = PowerpointApp.presentations.Open(myPath)
myPresentation.SaveAs (ws.Range("wk_dir").Value & "\test_earlybind.pptx")
Set myPresentation = Nothing
Set PowerpointApp = Nothing
End Sub
Late Binding Code Snipnet
Sub LateBinding()
Dim ws As Worksheet
Set ws = ThisWorkbook.Worksheets("Sheet1")
Dim PowerpointApp As Object
Dim myPresentation As Object
Set PowerpointApp = CreateObject("Powerpoint.Application")
PowerpointApp.Visible = True
Dim myPath As String
myPath = ws.Range("wk_dir").Value & "\" & ws.Range("ppt_name").Value
Set myPresentation = PowerpointApp.presentations.Open(myPath)
myPresentation.SaveAs (ws.Range("wk_dir").Value & "\test_latebind.pptx")
Set myPresentation = Nothing
Set PowerpointApp = Nothing
End Sub