Greetings!

You'll probably want to fill in the form as described in the topic: Welcome to Forum: In-Game Bugs!

Without this, bug reports are usually not accepted nor forwarded at all.

As for the issue, if other people are able to enter the battle just fine on your server, there might be something going on between you and the server. That is, it might not be something you can do anything about, if the issue is at a router server somewhere out there.

One thing I'd try, if you haven't yet, run the file check either via the PlayOnline Viewer start screen, or trigger it via the option hiding in the FFXI Config Utility.

Good luck!