After checking out from Subversion (SVN) you need to run any of the Ant targets for the workspace to recognize if it is the Community or Enterprise Edition, for example:
This copies files into the right location and creates the res/edition.properties file to flag that this has been done.
After checking out the project, there will be errors in the IDE as some source files (i.e. Web Services stubs) are not yet generated. The errors will disappear after configuring and building SignServer.