weird cpu spike

hi there,
i'm new to the list, hello everyone.

i have built a jitter patch that basically just chooses between a number of mjpeg files and plays them back with no processing or effects. the patch runs fine, with activity monitor giving a cpu use of about 25%.

if i then go into the cpu status page and turn the dac on, it spikes up to 100% and max goes super slow, beach ball style. it's fine when i turn the dac back off.
this happens even when the patch is not running, just open. it happens when the patch is not in the folder with it's movies and they're not loaded. i tried changing the soundcard with no difference.

one bit of info i got was that when i built an app from it i got the errors:

error:jit.qt.movie : could not initialize SOC sound playback engine
error : send~ : no such object
error : jit.qt.movie : could not initialize SOC sound playback engine (send~ class)
error : sfplay~ : no such object

i got this suite of errors for each of the jit.qt.movie objects in the patch, however i am not using soc or spigot~ and there are no send~ or sfplay~ objects anywhere in the patch as i have not started working on the sound yet.

the problem is that i need the dac on as i will be building an msp patch to control the corresponding soundtrack.

does anyone have any idea why this might be?

thanks for anyone's help

owen