The Sixers have problems with crappy teams that play the drive and kick game like NJ and Golden State. Their normal defense doesn't work, because the passing lanes aren't the same. They can win these games, but to do so requires discipline.
The first thing the team needs to realize is that the other team plays a gimmick offense, because they don't have the athletes to play straight up. The next thing to realize is that they aren't good shooters or good defenders, but they do present a problem that has to be dealt with.
It wasn't the Nets scoring that was the problem, it was that the Sixers weren't scoring. They were lazy and frustrated, because they couldn't run up and down the floor or force turnovers like they normally do. Its the same thing all over again- an undisciplined team failing to work to get good shots and beat the other team up in the process.
Also, why are the asking Speights to shoot from the outside. How STUPID! Post him up and let him score inside, where the Nets are weakest and vulnerable.
This is the fault of the coaching staff. At times they have shown that discipline and ability to function in the half court and win even without their running game. They better remember that, or they'll keep loosing to teams like that.