I'm just having an experiment at the moment, trying to get a development environment running on a Windows 7 64 bit box. It's actually going quite well - only a few hiccups along the way with mxmlc not liking JAVA_HOME to point at the JDK (which is fine under XP), but it does like it pointing at the JRE within the JDK.
Once everything was up and running, I tried to test my application. It kind-of works, but is unable to load the themes. The themes are compiled from a CSS file using MXMLC, and result in a file called Theme.swf. This is loaded using the application styleManager.loadStyleDeclarations method.
On my desktop machine, connected to the internet, this all works fine.
On this test machine, which is not connected to the 'net, because it's a corporate build, the styles don't load. In the console, I see...
[SWF] /ILM/index.swf - 6,575,011 bytes after decompression
[SWF] /ILM/styles/Theme.swf - 165,925 bytes after decompression
Error: Failed to load policy file from http://fpdownload.adobe.com/pub/swz/crossdomain.xml
Warning: Failed to load policy file from http://fpdownload.adobe.com/crossdomain.xml
*** Security Sandbox Violation ***
Connection to http://fpdownload.adobe.com/pub/swz/tlf/18.104.22.1685/textLayout_22.214.171.1245.swz halted - not permitted from http://localhost:8080/ILM/styles/Theme.swf
Error #2048: Security sandbox violation: http://localhost:8080/ILM/styles/Theme.swf cannot load data from http://fpdownload.adobe.com/pub/swz/tlf/126.96.36.1995/textLayout_188.8.131.525.swz.
Failed to load RSL http://fpdownload.adobe.com/pub/swz/tlf/184.108.40.2065/textLayout_220.127.116.115.swz
Failing over to RSL textLayout_18.104.22.1685.swz
Error: Request for resource at http://fpdownload.adobe.com/pub/swz/tlf/22.214.171.1245/textLayout_126.96.36.1995.swz by requestor from http://localhost:8080/ILM/styles/Theme.swf is denied due to lack of policy file permissions.