I'm current running HIPS7 P5 and we've had reported accounts of the dreaded red X when pdf documents are embedded into the web page.
disabling of IPS allow the PDF document to be displayed.
any ideas as to what policy in ePO would be causing this.
Sig 3793 is the "Adobe Reader and Acrobat ActiveX Control remote Code Execution Vulnerabilities"
If you go to the Description tab for the signature, you'll see the CVE links:
There will be information for the Adobe security updates that cover this vulnerability.
Install those and you can disable the signature.
The other option would be to create an exception based off your event.
I've seen those same problems with the about screen though I'm not sure if that indicates a corrupt VSE install or not. Have you tried uninstall/reboot/reinstall yet on any of these three systems to see if that resolves the issue? It may be worth a shot if it's a corrupted installation.