The Warriors looked up for the contest early on but at least three prime attacking chances were missed in the opening 10 minutes.
Twice Shaun Johnson was unable to find wing Jonathan Wright with passes going into touch and forward, but McFadden again suggested that a lack of familiarity affected their execution.
"We're just struggling to keep that same team in the park at the moment and that can have an impact," he said.
"Combinations are a big factor and that's what we missed tonight. We just missed a pass or the last person to finish a play. I know Shaun threw that pass over the sideline there where Jono Wright was just a little off where he should have been.
"That happens but you've got to be able to work your way through that. We probably could have tonight had we not made so many unforced errors."
Captain Simon Mannering blamed a lack of application and concentration for the mistakes which repeatedly allowed Melbourne off the hook just when they were looking vulnerable.
"We'd put a lot of effort in there defensively at times and then we'd let the pressure off and definitely made it a lot easier on the opposition," Mannering said.
"They get the territory pretty easily and we're defending our line again. It's frustrating for the whole team, [but] it's only us who can fix it."
Despite suffering their third loss of the season, which leaves the Warriors in 11th position on the competition ladder, McFadden was optimistic about some of their play.
"There was a lot to like about what we did tonight. I know the score line doesn't reflect that but certainly there were some patches there where we really looked good.
"There are some things that we're really building. Internally there's some things we are liking but you can't gloss over the fact we're just making it too hard for ourselves."