I've got the Zi8 too. Great little HD camera if you hold it still.

 I paid for QT Pro to convert the video where I can use it in Liquid but I have yet to be able to figure out which conversion is best. 

I've tried MOV to AVI which should work, but no. 

compression options include DV/DVCPRO-NTSC, 29.97 frame-rate, interlaced, and 4.3 (i'm not editing HD)

I can also  compress using dvcpro/pal, dvpal or none.

 I've tried exporting as Avid/2VUY which doesn't import into Liquid while AVID MpEG2 does, but takes forever.

 Anyone here using Quicktime Pro to successfully export file that Liquid takes without rendering.