Do you have CWM (Clockwork Recovery) as well as root?
If not, check this out and see if it's within your tech reach:
[RECOVERY] ClockworkMod 5.0.2.7 BML Officially supported by ROM Manager for Epic 4G - xda-developers
Here's a video that will take you into CWM step by step:
http://www.youtube.com/watch?v=xuLWzeJ1lT4
After that, you'll be able to flash a stock update or (even better) a custom rom with lots of goodies on it. Go and cruise over here and see what EL30options appeal to you:
Epic 4G Android Development - xda-developers
If you are rooted, the new system (EL30) update will not install OTA on your Epic. If you try, you'll get an Exclamation Mark cartoon (Fail notice). Pull your battery and reinsert it and you'll be back where you started, with no more notices.