The problem you're having is (probably) not directly caused by Optifine. There are lots of people (including all devs) that can use Optifine just fine.
However there seem to be some people for which installing some mod (Optifine and/or some other I forgot) and/or having some specific video driver causes the screen to flicker and/or the game to crash when clicking the Render button.
We have yet to find someone that can competently help us find the source of this behavior (as none of the devs can reproduce).
We do know of a potential workaround (that has not received a lot of testing though, again because of a lack of people being able to reproduce it) that we intent to include in the 2.0.0 release.
If you can build the Replay Mod yourself then all you need to change is replacing this star with an "x". If you don't know how to build it yourself, let me know and I'll provide a test build for you asap.
Hmm.. that GL error and the fact that you can only see a specifc part of the screen (haven't had that with anyone before) gave me an idea. Could you give this version a try? If it works, it'll look odd but no longer completely blank. Then at least I'll know what could cause it (and you could render your video).