Brook, when i worked at the vet clinic, i heard the vets telling stories about dogs who were afraid to have there nails cut. It could be because one time it might have cut to deep and her him/her, and he/she is scared of it now, i would pressure your dog if it's scared, it definitly won't do anygood (i mean like holding her down or something..i knew someone who did that-its stressful)

I was watching a show the other day on how to cut your dogs nails. rub the dogs legs and paws and inbetween the toes so it gets used to you handling them, once he/she is more comfortable with it, you should be good to go :]

If you still can't get it to work, you could always do what i do and get them cut when the dog is in for its vaccs or check up.