Gers' administrators confirmed on Sunday an offer made to buy the financially-stricken club by Green's consortium had been accepted.
The former Sheffield United chief executive has made it clear a CVA is the consortium's preferred route out of administration rather than restructure the company and create a newco, with £8.5million in the pot for the club's creditors.
But Green, who claimed he was "mad" to buy the troubled club, admits HMRC and Ticketus are not certain to vote the agreement through.
He said: "No, we can't be confident. The major creditors, as everyone knows, are HMRC and Ticketus.
"Who could have imagined that Chelsea would beat Barcelona home and away? No one.
"On the same basis, we can't assume that HMRC and Ticketus are going to vote it through."
Speaking at a press conference on Sunday, Green stayed tight-lipped over the identities of the members of his consortium, but insists they wanted to take over the club "for the right reasons".
He added: "We are not dealing with people of disrepute."
Green did confirm there are Rangers fans among the investors and admits he has concern over their ability to make good decisions regarding the club.
He said: "I worry about them. Sometimes fans don't make good business decisions. The Sheffield United fans had a go at me because I wasn't a Blade and didn't love the club.
"I argued I thought that made be dispassionate because I could make difficult decisions without wearing my heart on my sleeve."
Green also responded to alleged comments made by former Blades boss Dave Bassett, who was sacked at Bramall Lane under the chief executive, to Rangers manager Ally McCoist.
"I read this morning a comment Dave Bassett made to Ally. He said, 'Watch your back'. Well, I find that sad," he added.
"I'm not offended. I'm a Yorkshireman and too old to get offended. But it's totally wrong.
"Make no mistake, Dave did a fantastic job at Sheffield United. But the new board wanted the club to have a change. So my job was to go in, get rid of Dave and appoint a new manager.
"Unfortunately, that is what chief execs have to do. My first job was to get rid of a legend - it would be like sacking Walter Smith or Ally McCoist here.
"But it was face to face, it wasn't in the back."