Yesterday, I was browsing on Guru and I got an error regarding Adobe Flash 9. I didn't take a screenshot of it, thinking it might've been a one-time thing... seeing I had never gotten it before.
However, tonight I got the same error with the same ad - this time, I did get a screenshot of it. I'm not so sure whether it's because I run with FireFox, because of Flash or if there's a problem with this particular ad, but the following occured:
Translated from French: A scrip of this animation is slowing down the execution of Adobe Flash 9. If the execution is not suspended, there is a possibility that the computer might stop responding. Do you wish to abort the execution process? [Yes] [No]
If [Yes] if chosen, the ad slowly. If [No], the browser doesn't reply for a few minutes (CTRL+ALT+DEL will show it as "Not Responding") then the question pops up again.
I actually doubt it's suspicious, but better be safe than sorry.