ok... found the solution! Turns out that in the font files used for bootstrap, the unicodes were changed for some of the icons. I understand they did this because of some issues with browser compatibility.
Here is the list of modfied/new unicodes:
lock - E033 bookmark - E044 camera - E046 fire - E104 bell - E123 wrench - E136 briefcase - E139 paperclip - E142 pushpin - E146
Found this info on a issue on twitter-bootstraps github proyect, check the link for details.
Hope it helps someone...
Pancho