We have an ASP.Net 2.0 application running off Server 2003 that has been running in production for over a year now. One area of this program serves PDF reports in a new window (via javascript window.open) once the user presses an associated button. However, a while ago the users started reporting the following error when they were trying to view their reports:File does not start with '%PDF'. I've searched around and found some references to this issue and it seems to be a generic error message whenever a properly formatted PDF is being opened. The strange thing is the PDF file on the server can be opened without error and I can manually path to the report from the web client and open the file (the files are saved to the server hard drive for backup purposes).
At this point I'm guessing that a mangled PDF file is being streamed to the browser but I'm not sure why. It looks like there were some Windows patches installed before this started to occur but I'm not 100% sure this led to the problem. We've tested various clients (XP, Vista, Server 2008) as well as clients with different installs of Acrobat reader but it's always the same error.
Has anyone seen this or have any ideas?
Thanks in advance