Eurovan A/C

I have a 2000 Eurovan that the dealer said needs an AC compressor. I replaced the compressor and had the system refilled with oil and refrigerant. Now the system builds huge pressure(300+) and when the compressor kicks on the motor dies becasue it can't turn the compressor. If the solenoid in the rear of the van was bad could it cause this? If not what would? The system was flushed when the new compresor was replaced.