Fears grew about the Glasgow club's financial situation yesterday when it emerged senior officials were speaking to investors about a possible £1.5 million loan.
The Easdale brothers James and Sandy and Laxey Partners are currently in talks about lending the club "working capital" in return for more shares in 12 months time.
The news has increased fears among concerned supporters that the SPFL League One leaders, who are currently operating at a loss, are in danger of going back into administration.
It also comes after claims that the club has rejected the offer from Dave King, the South Africa-based businessman and former director, to invest in the club.
But Wallace has played down "ill-informed" concerns about the off-field future of the club in an interview with Rangers TV and "categorically" denied there is any risk.
And SportTimes columnist Johnstone believes Wallace, who is currently carrying out a 120-day restructuring project, was correct to speak out about the issue.
He has urged him to continue to actively engage with supporters as the club attempts to make its way back to the top flight of Scottish football.
He said: "I think Rangers fans want answers. The chief executive has said that he wants more dialogue with the fans in the future and rightly so.
"He is to be applauded for starting to engage with each of the official fans groups, with launching the Ready to Listen initiative yesterday and for dismissing the threat of administration.
"But there is this situation now where fans want to know exactly what is happening at the club and what the future holds for them.
"If the club have turned down Dave King's offer to invest money - and that is a big if - then why have they?
"It is questions like this that fans need answered if they are to work with the club to get it back to the top of the game in this country.
"The fans will want to know where the club is at this moment in time before they re-invest in season tickets for next season.
"They will want assurances they can keep going forward. They are entitled to ask questions before they renew their season books.
"Fans will be sceptical and will want to know what is happening behind the scenes and I think the chief executive has to continue to speak to them."
Johnstone added: "The people involved at Rangers now are working to get the club back to the forefront of Scottish football. I have no doubt about that at all.
"But if somebody out there (King) is willing to put significant sums of money in to help them achieve those goals then why is the club not letting them?
"It is no surprise that fans are not happy if that is the case. I can understand their feelings."
Meanwhile, Rangers will meet Airdrieonians at Ibrox on Wednesday, March 12, at 7.45pm.