If you find a bug while playing Grand Creation, please use the PEQ forums to report it.
http://www.projecteq.net/phpBB2/ Grand Creation is used as EQEmu's test server so the bugs reported there will be seen by the same people that are here.
If you find a bug on your own private server, then you are better off reporting them here.
If you find a bug on another server, you're better off using their forums if they have them. Unless of course, a server admin asks you to post here instead.