Goals from Matt Sparrow and Paul Hayes looked to have put the Iron in command but Darren Currie's 72nd-minute penalty pulled Chesterfield back into the game and they would have forced extra time were it not for Marcus Williams' late clearance from under his own bar.
"We had a lot of opportunities and they had too many for our liking," said Adkins. "The game was far too open and we can't hide away from that. We're a great attacking force and we'll score a lot of goals. We played some lovely football at times but the game was far too open.
"If we look at the bigger picture of the Championship then we can't do that and expect to win games. We have got to either change the personnel or change the shape."
Adkins is hoping to strengthen his defensive ranks before Saturday's visit of Derby but is keeping his targets close to his chest.
"You'll have to wait and see," he said. "The defenders have been injured and we're getting situations where we've got to be better defending as a team. The lads we've got are working hard but ultimately it's about winning."
Chesterfield manager John Sheridan refused to be downbeat after seeing his side produce a performance that could have earned them a win on another day.
"I'm pleased with the way we tried to get back into the game," he said. "Obviously we're playing against a very good team but I think we put a lot of effort in but we have shown that we're a decent side and we could have got something out of the end of the game.
"The most pleasing thing is that we showed a good attitude and tried to get back in the game. No-one hid and we took the game too them at the end and we looked the stronger side."