Irvine-based Epicor Software, a developer of enterprise business software, said Monday afternoon that it has turned down an offer from Elliott Associates, L.P., to acquire the firm. According to Epicor, after thoroughly reviewing the proposal, it determined not to pursue the unsolicited proposal. Elliott Associates had approached Epicor with a buyout offer worth $9.50 per share on October 1st. Elliott is a major shareholder in Epicor, which closed at $6.61 per share on Monday. The offer was worth approximately $556M.