from Gearbox forums:
Borderlands DLC, Claptrap’s New Robot Revolution, is currently experiencing an achievement/trophy bug that applies to all platforms including XB360, PS3, and Steam.
The bug relates to the following 5 achievements
A: “What a party!”
B: “It’s so realistic”
D: “The Lubricator”
They must be unlocked in this order. If the first of these five (5) achievements is unlocked in any other order, any achievements above that achievement on the list will not unlock normally.
If your first unlocked achievement is B: “It’s so realistic” (and you continue to then unlock C, D, and E) then you will be unable to unlock Achievement A: “What a party!” until the fix has been implemented.
If your first unlocked achievement from the list above happens to be achievement E: “Tourist” then you will be unable to unlock the rest of the achievements (A, B, C, or D) until the fix has been implemented.
We currently plan to have this bug corrected in the 1.50 Title Update. The fix will be retroactive so players can still obtain these item requirements for the achievements. Once the fix is released in the Title Update, they will be awarded with the achievements as long as they have obtained the requirements for each of these achievements beforehand. The 1.50 Title Update is currently planned for release in October. Once we have more specifics on a date, we will let the community know.
We apologize for the inconvenience and hope to have this corrected as soon as possible. Jack Monkey Squat 21:29, October 3, 2010 (UTC)
GODDAMNIT! Ive been killing claptraps non-stop for the past 3 days trying to get lubricator, bobble-trap and what a party and i thought i wouldve definitely got them by now, so i thought something was up. Glad to know... Sort of. ~ One random guy 21:33, October 3, 2010 (UTC)