Continuity mistake: As Frasier and Niles are starting work on their book, Marty gets four snacks and a beer and sits down in his chair. He gets up and we see the two bags that were behind the beer and can of something are now in front of them. Marty never touched them during that time.
Continuity mistake: When Roz's date Ted returns her purse to her apartment, Bulldog answers the door. He barks at Ted and Ted nervously drops the purse. We see Bulldog close the door. He should have picked up the purse first, or he wouldn't have been able to close it. We do see him drop the purse in a chair as he heads to the kitchen, but we never actually see him pick it up.
Continuity mistake: Early on in the show, Frasier and Martin are having breakfast and we can see an orange napkin in Marty's lap. While he is talking, the camera angle behind his shoulder shows his left hand against his cheek. Right after that the napkin appears on the table to the left - with no time for him to have moved his hand and put it there.
Audio problem: There are two audio problems in this episode, both in the same scene. Frasier is in his apt. talking to Niles, Daphne, and Martin. After Marty says, "Wow, really?", we hear a couple of garbled words while Niles' lips move. Then as Frasier heads to the door, Daphne asks, "How'd he hurt himself anyway?" While she is saying this, we can hear a phone ringing faintly. It is not coming from on stage, no one moves to answer a phone, and it has no part of the plot.
Continuity mistake: When Lilith and Frasier are at Dr. Campbell's (the first time), he makes them tea. A shot shows him preparing it, pouring it, etc. But in the next shot, Frasier and Lilith are already holding their cups. There was not enough time for him to have passed them the cups.