Welcome to the forum! You should start your own thread and reference ones like this one if needed.

Please read the posts in this thread. You have referenced the reader, not Adobe "Acrobat". As such, the class AcroExch.PDDoc is not in your registry and can not be referenced. The reference should just be shown as "Acrobat" as previously explained. The acrobat DLL and TLB files will be in your "c:\Program Files (x86)\Adobe\Acrobat 11.0\Acrobat\" folder.

Since you only have the reader, you will have to use a third party program to merge PDF files as explained. Of course one can include more than one worksheet to create a PDF using Excel's method.