Try first deleting the build.xml from the project, then deleting the project, but without checking the box to delete from disk (which is not checked by default). Then create a new project with the same name, the files will all be there since they were not deleted.
Then I had to add this to this to the VM Arguments tab:
I am currently testing IDE installation under Linux.
IDE successfully installed using "install new software" feature in Eclipse.
(i had to enter "ide" in search text field, and then click "select all", and click "next" button. Because for unknown reason, title was blank and i could not select it with mouse click, but maybe it is due to my desktop theme configuration).