Googling around yielded no results, so after figuring out the problem I’m posting the solution here for anyone else having this problem.

The solution is short: you have to call drawToBitmapData() BEFORE the Context3D.present() call.

In my case with Starling I had to add the functionality in the Starling.render() function, between the call to mStage.render() and the call to mContext.present().

If you are calling mxmlc via ANT you’ve probably seen this error and had to resort to solutions like setting the ANT_OPTS or Java arguments for the SDK on every single computer that uses that build script.

The solution is actually much simpler than that, mxmlc allows you to set this in the ANT target itself. Just add the parameters fork=”true” to make it run on it’s own Java thread, and then set maxmemory to something like “1024m”.

It would have been nice if adobe had this in the documentation, but no such luck.

When this is written, flash builder 4 doesn’t have a native way that lets you use it, so we have to do a little mix. (Update: The update is out.)
The global error handler works by adding an event to the uncaughtErrorEvents property of the loaderInfo of the application.
There are currently two methods of getting it to work.

Method 1 - The backwards compatible one:

Here the code doesn’t crash in flash player 9/10, but the error handling will only work in 10.1.

if(loaderInfo.hasOwnProperty("uncaughtErrorEvents")){
	IEventDispatcher(loaderInfo["uncaughtErrorEvents"]) .addEventListener("uncaughtError", uncaughtErrorHandler);
}

private function uncaughtErrorHandler(e:Event):void {
	trace("Global error:", e);
}

Method 2 - The type safe one:

Get the Flex 4.1 SDK if you haven’t already and choose that one as your project’s SDK.

Now you can use the new global error handling like it was meant to be used:

import flash.events.UncaughtErrorEvent;

loaderInfo.uncaughtErrorEvents.addEventListener( UncaughtErrorEvent.UNCAUGHT_ERROR, uncaughtErrorHandler);

private function uncaughtErrorHandler( e:UncaughtErrorEvent):void {
	trace("Global error:", e);
}