When Meridith is visited in the hospital there's a scene in the middle where you can see light filtering in through blinds and onto her arm, yet in all other scenes the shadows are not there.
When Michael is trying to redo the IV, he has the balloons in his hand, after a scene change, they're gone.
Dwight says that the doctor is treating Meredith for rabies before symptoms set in, and he mentions lockjaw. Lockjaw is a symptom of tetanus, not rabies.
Angela tells Pam that she's having a vet do an autopsy on her dead cat. Autopsies are done on humans; an animal would have a necropsy.
Incorrectly regarded as goofs
At 0:26:26 when the camera zooms in on Michael, you can see the reflection of two cameras in the television. However, given the mockumentary style of the series, it actually makes perfect sense for there to be cameras in the scene.
Errors in geography
In the scene when Jim and Pam leave the Dunder Mifflin parking lot they pass a for rent sign that has an 818 area code. 818 is the area code for the San Fernando Valley, not Scranton PA. Also all the cars on the street have California license plates.