Is this because we are using an evaluation copy?
Hi
Thank you for contacting support. Well, we don’t recommend to test Aspose APIs using evaluation versions. You need to apply a valid license as stated in this documentation:
The evaluation limitations are documented there:
Please get a temporary license for 30 days and try the latest version at your end. You can download a latest version of Aspose.Pdf from the download page here:
http://www.aspose.com/community/files/51/.net-components/aspose.pdf-for-.net/default.aspx
You can learn all about how Aspose products are licensed by checking out the Licenses FAQ here:
Please feel free to reply in case of any confusion or questions.