...is not listed on my 360 dash board of unlockable goals for Bioshock even though I'm reading about it in the walkthroughs. Is this an Xbox live only achievement?

If you're not connected to Xbox Live, then you won't be able to get the Achievement because Bioshock had an update in April that added Plasmids and a couple of Achievements, which you won't be able to download.

Does anyone know how to get the achievment?

You have to complete the game on hard mode without using any vita chambers.

In other words you can't die.

i completed the game on hard with updates and even though i quit and restarted when i died, i didnt get it

Strange, the guaranteed way of getting it is too just turn off vita chambers in the options menu.

THen I have a question.

in the option menu I don't see no ''Turn vito chamber off'' Option, or ANYTHING simmilar to that. =| what to do? I know that when I die, I go back to the main menu screen (new game, load etc)

So even if I die and go there it still counts?

I just spent the last 3 weeks trying to get this achievement and I finally just completed it...and guess what?....no achievement! OMG IM SO MAD!

same here turned off vita chmber and completed on hard= no achve. I did let some little sisters die on the way to fontaine though. i wonder if this could be the problem?

It's glitched.

if u save then die and u respawn in one but then u load ur last save before u did will u still get the achievement

No, it's glitched. Follow the link above.

Some people experience the glitch, some don't. If you do experience the glitch, there's a link above that explains a way around it. Is that too hard to comprehend?