If your running into error with IntelliJ IDEA after upgrading to 9.0.3 you may want to try the tip below:
If you just upgraded from 9.0.2 to 9.0.3 you may want to invalidate your caches (File > Invalidate Caches … then restart IDEA). There was a change along the way to the Flex support that caused old indexes/caches to not work for some people. That resulted in most of the core Flex code to show as errors, and would break code completion. Error highlighting and code completion depend on the indexes created in the IDEA cache. After invalidating the caches and restarting, IDEA will need to re-index your project at startup.
Full Thread is here
Lee Brimelow has released an early alpha version of a snippets panel for Flash Builder 4. If your interested check it out here.
Ran into an issue today where when trying to upgrade and AIR project to Flex 3.3 I kept getting this error:

Luckily the fix is pretty simple. Download the fixlinks.sh script from the link. Copy it to your 3.3 SDK root, make it an executable and run it. You should now be able to run your AIR application with Flex 3.3.
Flex Bug –> http://bugs.adobe.com/jira/browse/SDK-19707
More information can be found here:
February 10th, 2009
admin
If you don’t want to have the Gumbo Fx Class in Flex 4 then votes for this issue in the Flex Bug and Issue Management System. If you don’t have an account create one and vote. Hopefully Adobe will listen to the community and do what’s right.
The issue can be found here: https://bugs.adobe.com/jira/browse/SDK-17854
I just saw this link to the FlexFormatter come across my friend Tom Cornilliac’s Twitter stream and I was very happy. One of my biggest issues with Flex has been a lack of any automatic formatting. I’m really glad that Ernest Pasour decided to run with this. To install just drop the jar file in you Eclipse plugins folder, configure your preferences, and your good to go.
December 10th, 2008
admin
I updated an AIR application to compile with SDK 3.2 from 3.1 and ran into the error below:
Process terminated without establishing connection to debugger.
Command:
/Users/dancashman/Applications/Adobe Flex Builder 3
Plug-in/sdks/3.2.0/bin/adl -runtime
/Users/dancashman/Applications/Adobe Flex Builder 3
Plug-in/sdks/3.2.0/runtimes/air/mac
/Users/dancashman/source/air_app/bin-debug/AIR-app.xml
/Users/dancashman/Cynergy/source/air_app/bin-debug
Output from command: error while loading initial content
I found the quick fix here: nabble.com
Summary:
Update your descriptor file namespace (yourApplication-app.xml)
New Value: <application xmlns=”http://ns.adobe.com/air/application/1.5” >
November 14th, 2008
admin
I’ve just started to play around with Merapi and I feel that it adds a whole new dimension to AIR. The Merapi website describes the project best “Merapi is a bridge between applications written in Java and those
running in and created for Adobe AIR™ (Adobe Integrated Runtime™).” Check it out here, the possibilities are endless!