What are the typical causes of clicks and pops in an audio file?
Clicking in an audio stream is typically indicative of some kind of discontinuity in the time-domain waveform. I'm not sure what you mean by "zeroed out and dc-offset corrected," but these sort of artifacts can be created via unsophisticated audio editing methods. If you're suggesting, though, that an all-zero (i.e. pure silence) audio file will cause this behavior, then there's probably some little implementation detail that's causing it. Examples:


Audible effects caused by turn-on/turn-off of the output audio amplifier. This is relatively common.
Significant differences between the initial/final sample values and the output level forced to the DAC when "idle" (I can't think of a sane reason why the designer wouldn't make the DAC output zero when not in use, but it's possible to do something else).