Mail app missing plug-in For some reason there are some e-mails that I get where I need to scroll down a lot to see the entire message. The message is filled with "missing plug-in" errors (and they do not include the small error to fix it). 

This problem occurs when I get emails with 'adds' on the side bar or on top. Also,  when I hit reply there's a long 'new lines' coming up between my response to the sender's email. 

How can I fix this? It displays without any problems on my iPhone.
I was having a very similar issue, all video or jpg image files were replaced by the "Missing Plug-in" in any email received or sent. After upgrading to the latest Java, deleting the java plist file, repairing permissions, and numerous other suggested solutions from various websites, I downloaded from Apple and installed the latest OSX 10.7.5 "combo" update. Problem solved!