How to merge 4 files with VBA

Question

I have 4 files that I want to automatically merge using Visual Basic for Applications Code. I've searched through this forum and it seems that first you open the first pdf with PDDoc and then you use PDDoc.InsertPages to add the 2nd PDF and so on. Note these 4 files are each one page long. I am using Adobe Acrobat Professional and no this is not a server based application that I am developing. I am not interested in Adobe Live Cycle Designer. I am having difficulty inserting the page. I do not know how to define/specify the iPDDocSource As Object. The code I have written so far is below. Note eventually I want this to be invisible (ie PDDoc), but being able to perform using AVDoc could also be useful. Thanks.
Dim Path As String, Path1 As String, Path2 As String
Dim Path3 As String, Path4 As String
Dim gApp As Acrobat.AcroApp
Dim gPDDoc As Acrobat.AcroPDDoc
Dim iPDDocSource As Acrobat.AcroPDDoc
Dim jso As Object
Dim gAVDoc As Acrobat.AcroAVDoc
Path = "C:\junk" & "\"
Path1 = Path & "1.pdf"
Path2 = Path & "2.pdf"
Path3 = Path & "3.pdf"
Path4 = Path & "4.pdf"
Dim WshShell As IWshRuntimeLibrary.WshShell
Set WshShell = CreateObject("Wscript.Shell")
WshShell.CurrentDirectory = "C:\Program Files\Adobe\Acrobat 8.0\Acrobat\"
WshShell.Run "Acrobat.exe"
Set gApp = CreateObject("AcroExch.App")
Set gPDDoc = CreateObject("AcroExch.PDDoc")
Set gAVDoc = CreateObject("AcroExch.AVDoc")
'Set iPDDocSource = CreateObject("AcroExch.PDDoc")
ok = gAVDoc.Open(Path1, "1") 'This works
ok3 = gPDDoc.InsertPages(0, iPDDocSource, 0, 1, 0)
'<-- Problem here with iPPDocSource
Set gAVDoc = Nothing
End Sub

Answer 1

I am an absolute hack when it comes to programming in Visual Basic. In the past as a Structural Engineer I have programmed a lot in Fortran, but I have also written programs in a lot of other languages as well. However, programming is not my primary job, but I am better at it than your first impression implies, but not by much. I accidentally omitted the Sub MergePDF() text at the top of the code. This routine is part of a larger program run from MS Excel VBA that is already complete. Yes I do tend to kludge stuff together until it works, thats what examples are for. Therefore I made multiple dims and other declarations that aren't necessary because I do not have a familiarity with the Adobe SDK. However, the Acrobat SDK is not as intuitively obvious to the casual observer as you would have me believe. It seems to be written more for the C and Java programmers. All of that aside you did help me solve my problem so thank you. Thanks Reinhard for the code that may give me other ideas to explore. The following code was all I required for my current application.
Sub MergePDF()
Dim Path1 As String, Path2 As String, Path3 As String, Path4 As String
Dim gPDDoc1 As AcroPDDoc
Dim gPDDoc2 As AcroPDDoc
Dim gPDDoc3 As AcroPDDoc
Dim gPDDoc4 As AcroPDDoc
Set gPDDoc1 = CreateObject("AcroExch.PDDoc")
Set gPDDoc2 = CreateObject("AcroExch.PDDoc")
Set gPDDoc3 = CreateObject("AcroExch.PDDoc")
Set gPDDoc4 = CreateObject("AcroExch.PDDoc")
chk1 = gPDDoc1.Open("C:\junk\1.pdf")
chk2 = gPDDoc2.Open("C:\junk\2.pdf")
chk3 = gPDDoc3.Open("C:\junk\3.pdf")
chk4 = gPDDoc4.Open("C:\junk\4.pdf")
mergefile = gPDDoc1.InsertPages(0, gPDDoc2, 0, 1, 0)
mergefile = gPDDoc1.InsertPages(1, gPDDoc3, 0, 1, 0)
mergefile = gPDDoc1.InsertPages(2, gPDDoc4, 0, 1, 0)
savemergefile = gPDDoc1.Save(1, "C:\junk\merged.pdf")
End Sub