Adams was fuming with the decision that dented Vale's hopes of reaching the play-offs - the result leaving his side trailing the last berth by seven points - and confronted the official at the full-time whistle.
"The referee was only the person in the ground who thought it was a penalty," he said. "I had a perfect view of the incident and Gareth has made a great tackle. I don't mind losing games of football but that is very hard to take.
"I did talk to the referee on the pitch but I was very careful in what I said to him. Referees can gang up on you and you can be in serious trouble so I just made my point in the right way and made sure I didn't use any bad language.
"I'm not saying my team played well because they didn't. The effort and commitment was there but the quality wasn't and the game had 0-0 written all over it."