Bill Shirron submitted his resignation as executive director of the $7 billion Arkansas Teacher Retirement System, Little Rock. The systems board will consider the resignation at a special meeting on Thursday. Mr. Shirron said he was not taking the blame for recent problems at the system, including a $40 million loss in investments related to Enron Corp. and other management-related problems. "I want to see if the majority of the board feels I need to resign, said Mr. Shirron, indicating he will stay on if a majority votes not to accept his resignation. "If you lose the confidence of the board, its time to go, he said.