Thank you for your post.
I am unable to replicate the problem with FileMaker Pro 11.0v4 running under Mac OS X Lion 10.7.1. That is, I pull down the File menu and select "Save/Send Records As -> PDF...", and I enter a checkmark next to the option "Create email with file as attachment". After saving the file, the message is generated with the attachment, I assign the Mobile Me account and send it to my work account. I also have no plug-ins installed except for AutoUpdate.
Let me know what I'm doing differently than you, and I'll try to replicate the problem.
Thanks for the response. I've done some more testing and I discovered two hidden objects on one of my layouts. I think at one point they were special characters I had used to highlight some text, however I can't remember. Anyway, I was doing testing and narrowed the problem down to a single line of text. I thought the font was causing the problem so I changed it to Times. Suddenly two dotted boxes with the letters "obj" appeared. Once I deleted those, all my problems with mailing a pdf from filemaker disappeared. This is an old layout (I've been using this database since 2008) so I can't tell you what I put in there that was causing the problem. It's interesting to me, however, that they didn't cause any problems until I installed Lion ... perhaps coincidence.
Thanks for looking into it for me.
It's not unheard of for version upgrades to OS or FileMaker to reveal issues that were previously tolerated...