I am using the widely used pdfsharp library www.pdfsharp.net to concatenate multiple pdf documents into one.

My problem is that my c# program works fine for any random pdf files. But when I am trying to concatenate pdfs that came out of Planetpress, the final document is corrupt. Surprising thing is that I am able to open the individual Planetpress pdfs perfectly fine.

Just curious to know if I need to make any setting changes in the suite?