Sorry to hear your still having tire problems. If this is too elementary please overlook.....just trying to help.
Are all of the spokes and nipples relatively smooth and are you using a rim strip to protect the tube?
After getting the tube and tire on the rim air it up to about 10 psi and "bounce it" all the way around the circumference of the tire. Let the air out, repeat. Then air it up to operating pressure. This process helps get any possible pinches and wrinkles out of the tube, given it wasn't pinched bad upon installation.