From the latest default code:
FILE NAME: user_camera.c
This file contains a set of functions that communicate with the CMUcam. It also requires a
modification to the “PicSerialdrv.c” file that is standard with the FRC distribution. This
modification allows the uart interrupt routine to buffer the CMUcam packets.
There is a “user_serialdrv.c” file but I don’t see a “PicSerialdrv.c” file anywhere. Where is it located?

See the README.txt file. The name was changed in the code but the comments in the code still refer to PicSerialdrv.c. Any reference to PicSerialdrv.c refers to user_serialdrv.