After reading your message, I tested safari with video content done through REAL. It played fine, and I don't recall having installed any plug-ins in Safari. But.... RealPlayer might help...
I hope you didn't use any good email to register in it!!! NEver use anything more than a mail that you use for registering and statistics etc ... real are real- pain in apple for spams.. i dont have the player and so far not installing either..