I guess you are making a mistake then
Sub PowerPointVideo()
Dim myVideo As String
If ActivePresentation.CreateVideoStatus <> ppMediaTaskStatusInProgress Then
myVideo = InputBox("Please enter title name ", "Add Title ")
If myVideo = "" Then
MsgBox "You enter nothing Operation Aborted!"
Exit Sub
End If
ActivePresentation.CreateVideo FileName:=Environ("USERPROFILE") & "\Desktop\" & myVideo & ".wmv", _
UseTimingsAndNarrations:=True, _
VertResolution:=1080, _
FramesPerSecond:=30, _
Quality:=100
Else: MsgBox "There is another conversion to video in progress"
End If
End Sub