You know ;D there's something thats called 'JavaScript' that can do all this
Anyway, the %message% idea.. i dont get it. You have to give someone a direct link with the message already stored in the url, and hope they are already logged in cause else they wont even see it. It ruins the idea of having a personal message.
And different language support is nice and all.. but its a file server, not a weblog or something. The most text that will be displayed are the names and the stats of the files that are being served. If you want to host your file server in a different language, then go ahead and be my guest. But i dont think that multi-language or personal message support should be considered more important than remote file deletion or folder creation.
If i get it all wrong, please correct me. But this is just my opinion