Convert PDF to string using acrobat dlls - vb.net

Question

I am working on a vb.net project. I am trying to convert the content of a pdf file to string using acrobat dlls (cannot use other 3 rd party dlls). Below is my code, when I run the program I am getting the following error: "Retrieving the COM class factory for component with CLSID, failed due to the following error: 80040154 Class not registered". I did some research and found out that I have to install the full version of acrobat standard or professional version. Not only that the full version of acrobat must also be installed in all the user machines that the program runs.
Can anyone tell me if this is true and suggest how to fix the class not registered error?
Sub Main()
Dim s As String
Dim sSourceFile As String
sSourceFile = "P:\Report images\DevReports\New Folder\UM-STD-Approval_154.pdf"
Dim oSourceFileInfo As New System.IO.FileInfo(sSourceFile)
Dim st As New AcroPDDoc
st.Open(sSourceFile)
s = GetText(st)
Dim oAcroApp As Acrobat.CAcroApp = New Acrobat.AcroApp
Dim oAcroAvDoc As Acrobat.CAcroAVDoc = New Acrobat.AcroAVDoc
Dim oAcroPDDoc As Object = Nothing
If oAcroAvDoc.Open(sSourceFile, "") Then
'Set PDDoc object and save the file.
oAcroPDDoc = oAcroAvDoc.GetPDDoc()
' oAcroPDDoc.Save(1, sOutputFile)
Else ' Document FAILED to open.
MsgBox("Cannot open ")
End If
oSourceFileInfo = Nothing
oAcroApp.CloseAllDocs()
oAcroPDDoc = Nothing
oAcroAvDoc = Nothing
oAcroApp.Exit()
oAcroApp = Nothing
End Sub

Answer 1

Apologies for the obvious answer but you've kind of answered your own question already.
Adobe Reader is a free application with a very limited interface allowing automation; in practice it's limited to the point where you can display a PDF file and navigate through it (to some extent).
For full features automation (like what I think you are looking for) you will need to install the full Adobe Acrobat. And yes, any system you run this on will also need to have Adobe Acrobat installed.
Now, there are probably libraries out there (including libraries from Adobe or containing Adobe technology inside) that will allow you to embed the functionality you are looking for in your application, but those too will not be free...