This is one of the thousands of cases filed by RIAA member companies against individuals for P2P file sharing. EFF filed an amicus brief on behalf of the defendant asking the court to reject the recording industry's claims that file sharing infringes the distribution right. (According to the recording industry simply "making available" a file on a P2P network infringes the distribution right.)
EFF's brief in this case argues that a copyright owner's distribution right only reaches material objects -- in other words mere transmissions never infringe the distribution right.
Before the court was able to rule the recording industry voluntarily dismissed the case explaining that they had mistakenly sued Mr. Dennis for activities by his daughter.