sorry i should have said I havent been able to create any projects due to the fact that when i updated to ubuntu 12.04 greenfoot would not open when i press the icon it flashes(thats normal) and nothing happens? i have tried reinstalling reinstalling java changing java and using a different computer but it still won't open? Please can any ne help?

Please see the support page. In particular we need the debug log if you can possibly find it. Usually it's in (home)/.greenfoot/greenfoot-debuglog.txt, but ".greenfoot" may be hidden.

Hi Nic, After a quick test it seems that they've changed the format of the JVM paths in 12.04 which causes Greenfoot to fail to launch. We'll release a new version fixing this at some point, in the meantime the best solution for now is to use the generic installer rather than the deb file, which should work fine.

I had this same problem, you can avoid the .deb install problem by installing the Java JDK manually with the tar.gz files from oracle (rather than the easier repository install). I used the guide here: http://www.wikihow.com/Install-Oracle-Java-on-Ubuntu-Linux. it's a bit longer and more tedious but it gets the job done if you really want to use the .deb installer. This also works to avoid problems on other IDE's if you happen to use more than one, I also use bluej, which has the same problem with the .deb installer.