Regan, who also defended Scottish Football Association president Campbell Ogilvie's role during his time as company secretary at Rangers when some undisclosed payments were made, warned the crisis was causing "collateral damage" to the game.
The SPL commission chaired by Lord Nimmo Smith this week fined the company that formerly ran Rangers £250,000 but decided not to strip the club of any titles.
Regan told a news conference in Edinburgh today: "Now is a very good time for all parties to draw a line under what's gone on in last 12 months.
"It's crucial with league reconstruction being such an important issue that we draw a line under what's happened and seek to work collaboratively.
"If we spent as much time focusing on building and growing the game on the pitch as we do talking about conspiracy theories, exit strategies and matters off the field, I think we would be world class.
"We have to avoid the rest of the game becoming collaterally damaged. It's not about trying to find scapegoats for what's happened."
Regan, whose own position has been questioned by some in the game, insisted he would continue to look forward, and said that Ogilvie had been totally open about his role at Rangers.
He added: "Campbell Ogilvie played no part in the management and organisation of any element of the Murray group remuneration trust.
"He has been transparent and up front and he was the only member of the old [Rangers] regime who put himself forward to be interviewed by Lord Nimmo Smith and that says a lot about the man."
Regan insisted no deal had been done with Rangers to stop the club being stripped of their titles, but that the possibility of it happening had been mentioned to the new owners.
He said: "When the consortium approached the SFA and were interested in buying Rangers FC they asked for an outline of what were the worst possible punishments.
"The reason they wanted the information is they had investors who wanted to know exactly what the implications were, so what came on to the table was literally every possible sanction and issue."