When you develop a flash site/application logging while testing on your local machine is no problem.
I many cases it is also important that you also can log from your live site because things behave differently. It depends on the logger you are using. If you e.g. use the build in “trace” you get nothing when you browse the livesite.
I am also using trace but with MTASC and Zeroi and SOS as my log tool. SOS uses XML socket connection and when browsing the livesite Zeroi with SOS Publisher tries to connect to localhost. But localhost is a different domain than the livesite e.g. yourdomain.com so this is a crossdomain access. If you want to enable logging to localhost you have to start a webserver (Apache, ISS) on your local machine and place a crossdomain.xml in the root-directory with the following content:
I am using WAMP for my local setup.
Don’t forget to remove the logging on your livesite when things are done otherwise anybody with a local webserver, the crossdomain.xml and SOS running is able to see your logs 😉