You know what... i have been having trouble with my bt848 based card... It seems to have problems after X starts... but it is ok before that ( i can use streamer and stuff)
Try this...
Startx the way you normally do ( you may wanna try loading the "V4L" module) and then rmmod out your iomega drivers, and then modprobe them back in...
I have to do that with my bt848, but than again i have 7 videocards hooked up to my computer... and i don't have to do that if I only run one of them
Hope that helps
- r0gu3