(Can also skip to 5mins in to see what the defense has to say.)
Basically, the defense got information of Martin having texts that indicate him having a proclivity for fighting. There are also images of his physique. But this information was relayed to the defense until June 4th, not giving them enough time to seek out who these texts went to. The state basically kept this information from them for way too long.
Even though Martin had two levels of security on the phone, the judge is arguing that someone else could have sent those messages. Given the giant, undeniable relevance to the self-defense issue, I'm shocked that the judge is thinking about keeping this information away from the jury. If that does indeed happen, and Zimmerman is found guilty, the man will have a huge case for an appeal.