If you already have MyEclipse 4.0GA or 4.0.1GA installed, you can update it through our update site by selecting Help > Software Updates > Find and Install... > Search for updates of currently installed features and following the prompts. When asked, restart the workbench to complete the update. If you experience any obvious problems after the update, the issue is likely that the Eclipse plugin cache got stale as it sometimes does not cleanly rebuild after updates. To rectify the problem you'll need to restart Eclipse with the -clean flag one time: eclipse.exe -clean
That should resolve any issues.
NOTE: Please do not try to install 4.0.2 over any existing installation using the double-click platform installers as these are intended for new installations only and may result in an unstable configuration.
If you don't have MyEclipse 4.0GA or 4.0.1GA installed, please see the area titled 'Downloads MyEclipse for Eclipse 3.1' in the Downloads section to obtain the full installer for your platform.
To find out the differences between the Standard and Professional versions, please see this link:
You'll need a fresh Eclipse 3.1.x SDK (final) installation and JDK 1.4.2_05+ or JDK 1.5 on Windows or Mac, and *only* JDK 1.5 on Linux.