Um, dude, think about it...
If you're using Firefox, make sure to allow cookies from "ungrounded.net" with out the quotes of course. Also, if you right click in the game, under the settings option make sure that you let stuff be saved there too, it's under the tab with the folder on it. I got it to work for me this way. AND my computer's a little quirky, so you know that it's Obviously USER ERROR if it don't work for you now. Hehe, Linux R0X0R5 by the way...
Now, as for the game itself, I HATE with a PASSION having to go back to a level every freaking time I get a fragment. Please, if you value the lives of your unborn children and yours, as well, FIX IT! Cuz it gets really BoRiNg having to go back and play the level through over and over again, not to mention AnNoYiNg!