Factual errors: Mulder's waterbed is shown with a leak spraying water in the air. This might happen if one or more people were lying on the bed or pressing down on the mattress, but the fountain continues to spray when he is out of the bed. Waterbed leaks don't spray so much as ooze. Furthermore, the amount of water lost to cause the degree of saturation on the carpet (not to mention leaking into the apartment below) would mean that the bed would have lost most or all of its water, leaving Mulder waking up lying on the bottom of the mattress box.
Continuity: In this episode, a key event revolves around Mulder's water bed bursting which exists theoretically because of the Dreamland episodes. However, at the end of _"The X Files" Dreamland II (1998)_, 'time snaps back' with Scully summarizing the event as making the day as if it never happened. Therefore the purchase of the water bed by Morris (as Mulder) would not have occurred. So there shouldn't be a water bed in any following episode.
Errors in geography: The episode takes place in Headquarters in Washington DC but in the scene when Mulder is walking to the bank, Los Angeles City Hall is clearly shown in the background
Continuity: In the episode "Monday", Mulder's Omega watch displays the time and the day of the week. In the episode "Arcadia" it displays the time and the date.