Acrobat cannot read .FDF written with Excel VBA - vba

Question

I exported a PDF with form fields in FDF and wrote a sub to output another FDF verbatim, with cell values for the form field values. If I edit the FDF in a text editor and change the values, Acrobat can read the file just fine, but the file output with VBA throws an error:
Adobe could not open whatever.fdf because it is either not a supported file type or because the file has been damaged
I've tried two different types of line breaks, I've tried a similar sub with xfdf formatting which is slightly different with the same results.
Sub something()
Dim sht As Worksheet
Set sht = Sheets("owssvr")
Dim lastrow As Integer
lastrow = sht.Cells(sht.Rows.Count, "A").End(xlUp).Row
Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")
Dim Fileout As Object
Dim x As Integer
For x = 2 To lastrow
Set Fileout = fso.CreateTextFile("C:\Users\blabla\" & x & ".fdf", True, True)
Fileout.Write "%FDF-1.2" & vbCrLf & _
"%âãÏÓ" & vbCrLf & _
"1 0 obj" & vbCrLf & _
"<</FDF<</F(MyDocument.pdf)/Fields[<</T(Adobe Form Field)/V(" & sht.Range("U" & x) & ")>>]/ID[<4ED54800AC4A3D41ABE4F4C7B12A3D23><609E705B7532334B8F914CFF4C09F2A0>]/UF(MyDocument.pdf)>>/Type/Catalog>>" & vbCrLf & _
"endobj" & vbCrLf & _
"trailer" & vbCrLf & _
"<</Root 1 0 R>>" & vbCrLf & _
"%%EOF" & vbCrLf
Fileout.Close
Next x
End Sub

Answer 1

Simply leave out the line: "%âãÏÓ" & vbCrLf & _". /ID and /UF keys not really needed.
Something like this should work:
Fileout.Write "%FDF-1.2" & vbCrLf & _
"1 0 obj<</FDF<<" & vbCrLf & _
"/F(MyDocument.pdf)" & vbCrLf & _
"/Fields" & vbCrLf & _
"[<</T(Adobe Form Field)/V(xyValue)>>]" & vbCrLf & _
">>>>" & vbCrLf & _
"endobj" & vbCrLf & _
"trailer" & vbCrLf & _
"<</Root 1 0 R>>" & vbCrLf & _
"%%EOF" & vbCrLf

Answer 2

You will find that in the Acrobat IAC documentation. Here a quick vbs(vba) example. Where you need only 2 lines from that: jso.getField and f.value =... Good luck.
'//-> Set a value for a form field via JSO
'//-> Settings
FileNm = "d:\TestInput.pdf"
FieldNm= "Input1"
FieldValue= "50"
'//-> let's start
Set App = CreateObject("Acroexch.app")
app.show
Set AVDoc = CreateObject("AcroExch.AVDoc")
'//-> open the file and put the value in
If AVDoc.Open(FileNM,"") Then
Set PDDoc = AVDoc.GetPDDoc()
Set jso = PDDoc.GetJSObject
'//-> Get the field and put a value in
set f = jso.getField(FieldNm)
f.value = FieldValue
end if

Answer 3

As much as I want to leave this open in hopes somebody figures out WHY VBA is screwing up the unicode, my problem can be solved without invoking fso at all and just using FreeFile and string replace on an original FDF
Sub blabla()
Dim objAcroApp As Acrobat.AcroApp
Dim objAcroAVDoc As Acrobat.AcroAVDoc
Dim objAcroPDDoc As Acrobat.AcroPDDoc
Dim jsObj As Object
Dim boResult As Boolean
Dim oldPDF As String
Dim NewFilePath As String
Dim sTemp As String
Dim iFileNum As Integer
Dim oldFDF As String
Dim i As Integer
Dim lastRow As Integer
Dim sht As Worksheet
Set sht = Sheets("owssvr")
With sht
lastRow = .Range("A" & .Rows.Count).End(xlUp).Row
End With
For i = 2 To lastRow
oldPDF = "\mydoc.pdf"
oldFDF = "\mydoc_data.fdf"
newPDF = "\" & i & ".pdf"
iFileNum = FreeFile
Open oldFDF For Input As iFileNum
Do Until EOF(iFileNum)
Line Input #iFileNum, sBuf
sTemp = sTemp & vbCrLf
Loop
Close iFileNum
sTemp = Replace(sTemp, "<</T(some form field)/V( )>>", "<</T(some form field)/V(" & sht.Range("E" & i) & ")>>")
iFileNum = FreeFile
oldFDF = "\" & i & ".fdf"
Open oldFDF For Output As iFileNum
Print #iFileNum, sTemp
Close iFileNum
Set objAcroApp = CreateObject("AcroExch.App")
Set objAcroAVDoc = CreateObject("AcroExch.AVDoc")
boResult = objAcroAVDoc.Open(oldPDF, "")
Set objAcroPDDoc = objAcroAVDoc.GetPDDoc
Set jsObj = objAcroPDDoc.GetJSObject
jsObj.ImportAnFDF oldFDF
jsObj.SaveAs newPDF
boResult = objAcroAVDoc.Close(True)
boResult = objAcroApp.Exit
Next i
End Sub