Rangers are in a "critical situation" following the decision of US businessman Bill Miller to withdraw his bid to buy the club.
The trucking tycoon, who was named preferred bidder last Thursday, confirmed yesterday that he would no longer be pursuing his interest in the stricken side.
Mr Miller said preliminary information he had received about the club was "more optimistic than reality", and also made reference to opposition to his takeover bid by Rangers fans.
Three other bids are on the table, one from the UK and two from overseas, according to administrator Duff and Phelps.
Andy Kerr, president of the Rangers Supporters Assembly, spoke about the "urgency of the situation", saying Duff and Phelps needed to "move with the utmost haste" to secure the club's future.
He told BBC Radio Scotland's Good Morning Scotland programme: "Let's be open, let's be honest, let's fully understand another false dawn is going to be the final nail in the coffin."
Asked if the game was up for Rangers, he replied: "I don't think it is up but we are in a critical situation and things need to happen very, very quickly.
"I very strongly urge Duff and Phelps and the people they are currently speaking to to move with the utmost haste now."
Mr Miller said he heard a "loud and clear" message from Rangers supporters.
The businessman also received "vitriolic" emails from fans, according to one of his advisers.
Jon Pritchett, chief executive of Club 9 Sports, said last night: "He was getting hundreds of emails every day - vitriol and expletive-filled - saying 'Go home Yank'.
"Bill felt like it was a pretty unwelcoming environment. He would have had to do a lot of things that would make him less popular."
Referring to the emails, Mr Kerr said: "It would be interesting to see one or two examples and just try and understand what sort of people were doing that.
"We saw a couple of banners and we're talking about a few people here, and it is disappointing when people are effectively prejudging the guy.
"The general call from the supporters was, 'Who are you? Give us an explanation of what you are trying to achieve. Let's try and work together and engage with you and see if we can take the club forward'. That's where we wanted to be."
He added that he was "not surprised" the American pulled out.
He said: "I just don't think that he had an understanding of the business, what was going to be involved to turn the club round, the precarious nature of where we are and where we're trying to get to.
"It just seems an odd scenario that someone from so far away was trying to buy into a 140-year-old institution."
Rangers went into administration in February after HM Revenue and Customs lodged a petition over the non-payment of about £9 million in PAYE and VAT since Craig Whyte's 2011 takeover.
It later emerged that the Glasgow club's £18 million bank debt was paid off with future season-ticket money from Ticketus.
Last month, the club were handed a £160,000 fine and 12-month embargo on registering players aged over 17 by the panel after being found guilty of five charges in relation to their finances and the appointment of Mr Whyte as chairman by a Scottish Football Association judicial panel.
Rangers' liabilities total about £60 million but they could face an additional tax bill of up to £75 million, depending on the outcome of a tribunal.
Earlier this week a Scottish Premier League vote on financial fair play proposals, which could affect Rangers, was adjourned again.
New rules would see greater penalties for clubs in administration, while clubs who undergo an "insolvency transfer event" could be docked 10 points for two seasons and see their SPL income slashed by 75% for three years.
What did emerge from the meeting was a proposal for all the clubs to vote on whether a Rangers spin-off club should be allowed into the SPL.
Under current rules, an application for transfer of shares to a newco would be ruled on by the SPL board.
Bids from Sale Sharks owner Brian Kennedy, the Blue Knights consortium led by former Rangers director Paul Murray, a Far East consortium led by Singapore-based businessman Bill Ng and a mystery German consortium were discounted by Duff and Phelps before Mr Miller was named as preferred bidder.