Hi,

This is a code access security issue. It may have to do with SharePoint configuration or ASP.NET security configuration. The first thing you want to check is whether your ASP.NET application is set to full trust:

http://msdn.microsoft.com/en-us/library/tkscy493.aspx

There are many different trust levels and you can customize the set of permissions granted for each trust level with configuration files on different levels (machine level, application level, etc). We require full trust because it needs to make a lot of API calls. SharePoint also defined several more trust levels that you can use. In theory you can fine tune those configuration files so that it only grants the application whatever permission it needs, but in practice it's almost impossible to get it to work with the PDF converter because the converter requires almost all "restricted" permissions --- file permission, network permissions, unmanaged code permissions, reflection permissions, ect.

Thanks!