That was the one where Abby's stalker ex-boyfriend comes around, isn't it? Bloodbath is that episode and that's season 3. I think that's the one where she ends up drunk in his basement and accidentally knocks a chunk out of his boat. The only real Abby centric episode in season 5 was Dog Tags, which had a lot of cute Abby and Gibbs moments but yeah, I think you're thinking of Bloodbath.