Adobe Flash Builder 4 is still in beta and is not yet available to purchase.
The beta is good for 30 days, and if you have a Flex Builder 3 serial number you can watch this page for more information on extending the Flash Builder trial http://labs.adobe.com/technologies/flashbuilder4/extension.html.
Flex 4 should be released in Q4 2009 (according to http://opensource.adobe.com/wiki/display/flexsdk/Gumbo), although dates are subject to change.
Please try the following steps found in the Flash Builder Release Notes:
If Flash Builder Beta fails to launch successfully after installation, or if you receive a Licensing error message during launch, here's the recommended workaround:
- Quit all running applications.
- Uninstall Flash Builder Beta.
- Making sure that there are still no other applications running, install Flash Builder Beta.
- In most cases, steps 1-3 should be enough, but if it still won't launch, a reboot can help as a follow-up.
If that doens't work, there are further suggestions in the release notes and in this thread which will hopefully help: http://forums.adobe.com/thread/440762?tstart=0
I'm having the same problem described above. I've tried the suggested steps of uninstalling, reinstallling with nothhing running and rebooting without any success. I also attempted changing the folder/file permissions suggested in the link, with no luck. I've only been running the trial for one day, so any help to evaluate it further would be helpful.