Im just curious,has anyone every had problems when the dog mounts the bitch the bitch clamping up and the dog not succeeding with a tie resulting in no pregnancy?

This would suggest to me that the bitch was possibly not being mated at the right time. Optimum mating time is vital if a successful mating is to take place & result in a successful pregnancy. I would recommend getting someone to take smears from the bitch (although this is not available at many places) or run some pre-mate tests. which can either be done at the vets, or if the vet takes a sample of blood, the kits are available to buy & are easy enough to do at home. :)

You seem to have 2 threads running here. See replies on the other one.