hi, not too familiar with bugreports, so forgive me for any errors and correct me! with the new portage-2.1 option EMERGE_DEFAULT_OPTS="--verbose" revdep-rebuild breaks when starting to reemerge broken stuff. This is because the emerge command looks sth. like this: emerge --oneshot --nodeps =dev-java/sun-jdk-1.5.0.06-r4USE="...." 0kb so emerge gives error about an unknown atom.
Most certainly not a bugzilla bug.
Upgrade your gentoolkit. *** This bug has been marked as a duplicate of 126575 ***