Er, as far as I know you have to manually open (Unless you're using something else) the Minecraft Jar and put it into that, not just the bin folder.

Unless someone changed that I wasn't informed of, that's how I've always done it.

Make sure it has it as minecraft.jar that screwed me up when I installed mods

Hm, I was looking up Optifine just now and the download that I found had several comments saying things like it was making their Minecraft laggier than without Optifine, that the grass had grey sides, and other comments like this.

Perhaps the most recent Optifine just isn't a good version of it and has some bugs that need to be fixed, that's the only conclusion I can come to with all these complaints I read, and that you've repeatedly been sure that you've done it correctly multiple times.

Glad to hear that you were able to get it installed! Sometimes things are just crazy like that, suddenly working.

Enjoy your time on the server then. ^^