this is the same thing i’ve found. I always now roto at double the frame rate when working with interlaced video. all you have to do is open up the comp settings and type *2 after the listed frame rate, then when you’re done type /2. You must separate fields for this to work. I’ve never ran into the problem of the par causing trouble but then I never do any actual work with par preview turned on because i beleive the warning
if you captured from the camera you had it set to downsize to DV. you’re not getting hdv, you’re getting widescreen DV so the size is right. if you want hdv then you have to set the camera to send hdv down the firewire. read the camera manual.