[Zubersoft]

Without knowing more, I'm guessing you may be tapping on a URL on the PDF page which is trying to load a separate PDF that doesn't exist. To check if this is true, try changing to another page first, then tap in the center and see if the same problem occurs. If that's not the issue, I may need you to send the PDF to mike@zubersoft.com (or share a link to it through a cloud service) so I can take a look at it.

Mike