Rosenberg said no "substantive actions" were taken during the SAG board's 30-hour-long emergency meeting.
He also said the board has no immediate plans to replace Allen, whom critics claim is hindering the signing of a new deal.
Rosenberg said in a statement that a group of board members submitted a document at the end of the board meeting "that purports to deal with the employment of" Allen, who also is the union's chief negotiator, and the "continuing approach to negotiations."
But, the statement said, the union's lawyers said the document was invalid for several reasons, "including a lack of sufficient signatures and the absence of any language on the document demonstrating the intent of the signers to grant their assent to the proposal."
He said Allen and the negotiating committee "remain committed to advancing the cause of actors and our crucial contract negotiations."
SAG and the Alliance of Motion Picture and Television Producers have been unable to reach a new contract since their last one expired June 30. SAG leaders have said they want to seek the approval of the union's 120,000 members to authorize a strike. The move has caused a rift between SAG members for and against the vote.
The meeting that ran from Monday into Tuesday failed to produce any major progress and no mailing date was set for the previously approved TV/theatrical strike authorization referendum, Rosenberg said.