Since April 3rd, I have had this error, constantly d/c'ing every 1-5 min. I was sitting around waiting for a fix from SE and decided to try some tests. I got a friend to load up on my account from his PC ( almost identical hardware ), and sure enough he had no problems on my account. I then used his account on my PC and I still had the d/c issue.
So now I realized that there is an issue between my Hardware or software. I started with a fresh format of my PC, ( I needed a nice clean up anyway, what better time than now ) and updated all drivers including network card. Error 30002 remained. I followed many steps I found on other forum posts, disabling fire wall on Win7 and modem, port forwarding, I ran a ping test on one of those sites, was perfect with no packet loss. Error 30002 remained. I finally decided to HARD reset my modem ( holding little button on the back of the modem for 30 sec ). ERROR 30002 WENT AWAY!!! I was able to play for about 4-5 hours until i got d/c with error 30002. Tried logging back in, got d/c within a few minutes, tried several more times and was still d/cing. Reset my modem AGAIN, was able to play for 6 or so more hours until i logged out for the night.
I have never modified any settings on my PC or modem previously and never had a d/c error 30002 issue before April 3rd. I really don't know why resetting my modem seems to be working for me, perhaps the reason why we are all having this problem AT THE SAME TIME is still on SE's end of things. I find it so curious that since April 3rd so many people are having this issue, so even though i found a fix that involves my hardware, I still think SE has something to do with it. I will be contacting my ISP on Monday to find out if they are aware of any issues on their network, and perhaps get a new modem and see if that permanently fixes it.
--- I just wanted to share the steps I took trying to figure this issue out, I hope this helps everyone. Please share your experience after you have tried resetting your modem. Perhaps if this fixes the issue for more people, this information may help SE fix the root of the problem.
-PS.- I do not have a router on my network, and i know this may be the cause of this error as well if you have one, try playing with that.