Thank you for your message.
I was unable to reproduce this issue using FileMaker Pro 11.0v4 and Mac OS 10.7.3. In my test file it worked as I expected.
When you said, "nothing at all happens" does that imply that the PDF is not being created?
Assuming the PDF is being created, you might want to double check that Apple Mail is your default email client / reader. In the Preferences of Apple Mail, click on the General tab and verify that Apple Mail is set as your Default Mail Reader.
Thank you for your prompt reply. I am using Mail.app as my mail client and I just checked to verify it was set as my default mail reader. To my surprise, something had changed it to Google Chrome without my knowledge. I retested my layout and everything is working as expected. Sorry for troubling you, but I would not have suspected that as a requirement for Filemaker to perform that function so it was time well spent. Thank you.