The Cowboys originally had a deal in place with Cleveland to trade the 28th overall selection and Alvin Harper for the 6th overall pick, which they wanted to use to take Willie McGinest. Parcells then drafted McGinest 4th overall, and the trade was pulled back. There's famous footage of Jones lowering his head to the table in the war room when the Patriots pick was announced.
He panicked later in the round, and believing that the Oilers wanted Carver, he traded the 28th and a second rounder to the 49ers for the pick that was used for Carver. The Oilers had no intention of taking Carver, and took Henry Ford. The 49er selections turned into William Floyd and Kevin Mitchell. Incidentally, the 49ers also traded into the Browns slot once the Cowboys pulled out of the deal, and took Bryant Young.
With the exception of the Allen selection, that is a draft to forget on many levels.
As far as Carver was concerned, he played at Arizona State at around 225 pounds. He bulked up to 265 pounds, and lost his first step quickness, which was his strength. Combine this with a non existent work ethic and a drinking problem, and you have a bust.