I'm trying to add the alternate title "Peridot" to the ペリドット series ( http://www.mangaupdates.com/series.html?id=133 ), but every time I try I get a message saying

SITE OFFLINE
Installing an enhancement. We\'ll be back in about 5-10 minutes! Sorry. (05/15/09)

Considering the fact that it's now 05/29/09, shouldn't those "5-10 minutes" be done by now? 😉

You don't really need to since Peridot is already the Main title

Hmm... I didn't notice that. I didn't think peridot was in there since it didn't show up when I searched (I had to get the japanese name of ANN & search for that in order to find it). ...But it shows up in a search now... 😕
I wonder if the not showing up in a search was a site glitch, or if I mistyped something, or if I was thinking of another series (I was looking up several series yesterday & 3 or 4 of them didn't show up when I searched, despite the fact that the name I had searched for was in the list of alt titles)?

...In any case though, the bug still exists & should be seen to whenever the staff gets a chance.

"Peridot" has been the main title for that series for at least a year...

We don't allow duplicate titles (dunno if the system can check if for duplicate kanji titles though...), which is why you're getting the error (since it's already in the main title), but you're right about the error being misleading and stupid. The admin error I get is only slightly better...

A just ruler amongst tyrants