With Subversive it may happen that it completely ignores some projects while it perfectly works for other ones. If a project seems to have no SVN information in Eclipse (thoug it actually contains all the .svn/ folders) and the Team context manu only contains Apply Patch… (i.e. especially not Share project…) then you have likely mixed up Eclipse metadata about the project (for instance by sharing it previously with Subclipse).
This is a well known problem and the solution is to Delete the project (without deleting its content) and to re-import it into Eclipse. Also make sure that the Subversive back-end version supports the version of Subversion (too many *versions here :)) recorded in the project metadata. If needed, you can use a script to up/down-grade the SVN metadata, as described in a FAQ.