When i get a penalty (for overspeed in pit), if i enter the pit in the last lap, i'm disqualified.

That's a bug ?

nope, it isnt.
cause when u get drive trough penalty, u need to drive trough the whole pit.
but the finish line is before the end of the pit.
so its not a bug

maybe not a 'bug' in the strictest sense of the word, but an oversight it would definately seem to be. Seems more useful here than in the improvement suggestions forum, to me...

Quote from [RCG]Boosted :

nope, it isnt.
cause when u get drive trough penalty, u need to drive trough the whole pit.
but the finish line is before the end of the pit.
so its not a bug

Ok...

Example : 30 laps race, i get a penalty in lap 29, i entered pit in this lap => disqualified but how could i do anyway ?. It's a bit disappointing ...

hehe, yeah its maybe not good, but its the way how it is
and for ur example, when i would be so close to the end of the race,and had to pit, i wouldnt drive near the limit

Quote from David.V :

Ok...

Example : 30 laps race, i get a penalty in lap 29, i entered pit in this lap => disqualified but how could i do anyway ?. It's a bit disappointing ...

Don't you just get a 30 or 45 seconds time penalty when you get a penalty in the last lap?

The Problem should only occure, when you have been lapped by the leader and you get a DT in lap 28 e.g.?

yes, that shouldn't happen. You get a time penalty in the last 3 laps. In the last 3 laps of the race, not yours. So if you are more than 3 laps behind the leader, you can still get a DT penalty.
Another problem are time based races, where you always get a ST or SG penalty.

See this thread: http://www.lfsforum.net/showthread.php?t=1277