@diamondburned:

One more thing is that in the Opera 30, the PPAPI version is 17,0,0,188. Meanwhile in Chromium it's 18,0,0,160.

Okay, so now your problem is solved. I guess there are different versions because Chrome use another installation then the one Opera use. You will just have to wait for an update.

did installed version 30. But what I don't like in it is that Opera keeps starting a lot of instance in my system.

It has one "instance" for every tab, which actually increases the performance (so it's a good thing).