Not able Read PDF version 1.2 PDF documents

Hi,
 
We are using below mentioned dll for my web application.
 
1. AFormAut 1.0 Type Library (Interop.AFORMAUTLib.dll)
2. Adobe Acrobat 7.0 Type Library (Interop.Acrobat.dll)
 
Source Code:
 
Dim formApp As AFORMAUTLib.AFormApp
 
formApp = CreateObject("AFormAut.App")
 
Dim script As String
script = "for (var p = 0; p < this.numPages; p++) { var numWords = this.getPageNumWords(p); var ckWord; for (var i=0; i
Using these references and coding we are reading PDF document content. But we not able read only PDF version 1.2 PDF documents and other versions 1.3, 1.4, 1.5 and 1.6 etc we can able to read. even we tried with Adobe Acrobat 9.0 version type library, it's not able to read only PDF version 1.2 only
 
Note: The PDF file is created through Acrobat Distiller 5.0 version.
 
Please let us know why its failing and what we need to change for this make it work.