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);
}

Associated Extension box: .FLV
MIME Type box: flv-application/octet-stream

and for f4v (technote):

Associated Extension box: .F4V
MIME Type box: video/mp4

Digging around the internet, I’ve found people reporting these MIME types working too;
video/x-flv for .flv files, and
video/f4v for .f4v files.

Be advised that you may have to restart IIS for the changes to work.

Simply add this to your page’s stylesheet:

a:focus, object:focus { outline: none; -moz-outline-style: none; }

So this is the deal: I always embed my flash using the html code that SWFobject recommends:

<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="780" height="420">
  <param name="movie" value="myContent.swf" />
  <!--[if !IE]>-->
  <object type="application/x-shockwave-flash" data="myContent.swf" width="780" height="420">
  <!--<![endif]-->
    <p>Alternative content</p>
  <!--[if !IE]>-->
  </object>
  <!--<![endif]-->
</object>

After the upgrade, instead of my pretty flash objects I get this funky arrow in my posts:

–>

And if I look at the source, it now looks like this:

<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="780" height="420">
  <param name="movie" value="myContent.swf" />
  <!--[if !IE]>&#8211;>
  <object type="application/x-shockwave-flash" data="myContent.swf" width="780" height="420">
  <!--<![endif]-->
    <p>Alternative content</p>
  <!--[if !IE]>&#8211;>
  </object>
  <!--<![endif]-->
</object>

Apparently wordpress replaces
<!--[if !IE]>-->
with
<!--[if !IE]>&#8211;>, but when I look into my post to edit it, it still looks fine there.

The reason is that wordpress is trying to make your writing prettier, even if you don’t use the wysiwyg editor. To stop wordpress from doing that, go into your wordpress directory and edit the file wp-includes/formatting.php. On lines 55 and 56 (for version 2.8.5) you should see this text:

$static_characters = array_merge(array('---', ' -- ', '--', ' - ', 'xn–', '...', '``', '\'s', '\'\'', ' (tm)'), $cockney);
$static_replacements = array_merge(array('—', ' — ', '–', ' – ', 'xn--', '…', $opening_quote, '’s', $closing_quote, ' ™'),

If not, just look for it, it should be in the top page or two.
Now all you have to do is comment out the array elements you don’t want wordpress to replace. My lines look like this:

$static_characters = array_merge(array(/*'---', ' -- ', '--', ' - ', */'xn–', '...', '``', '\'s', '\'\'', ' (tm)'), $cockney);
$static_replacements = array_merge(array(/*'—', ' — ', '–', ' – ', */'xn--', '…', $opening_quote, '’s', $closing_quote, ' ™'),

Hope this helps.

The first thing you have to do is create a new flash file to store the font(s). Then, right click the library and select “New Font…”.

Choose the font you want to embed and give it a name. Any name will do here, as this is only the library name and will not affect our code in any way. I prefer to name the font with the same name as the linkage name I plan to give it.

Click ok, and then right click the font in the library and select “Linkage…”. Check the “Export for ActionScript” and “Export in first frame” options, give your font the linkage name of your own liking and click OK.

And now you’re ready. Export the file to swf and there’s your font resource file.

If you want to use that font, you first have to load it into the application domain, and then register it on the global font list using the Font.registerFont function. The textfield can’t display it until it has the embedFonts property set to true and the font name in its textformat.
You can see an example in the following code, ready to be pasted into your frame:

var l:Loader = new Loader();
l.contentLoaderInfo.addEventListener(Event.COMPLETE, onLoaded);
l.load(new URLRequest("MyFont.swf"), new LoaderContext(false, ApplicationDomain.currentDomain));

function onLoaded(e:Event):void {
	// Register the font to the global font list
	Font.registerFont( Class( ApplicationDomain.currentDomain.getDefinition("MyFont")));

	myTextField.embedFonts = true;
	// instantiate the font just to get the real font name, or if you know the name before hand you can just hard-code it in here
	var fontName:String = new (ApplicationDomain.currentDomain.getDefinition("MyFont"))().fontName;
	var tf:TextFormat = new TextFormat(fontName);
	// Set the text format for the text already in the text field
	myTextField.setTextFormat(tf);
	// and for future changes
	myTextField.defaultTextFormat = tf;
}