Orange County Performing Arts Center’s main presenter might have to cancel part of its season if it can’t raise $500,000 in a hurry. “The Philharmonic Society, which presents touring artists, reported a $756,000 deficit for 2006-07, its first season using the new Renée and Henry Segerstrom Concert Hall as its main venue. Attendance was 74% of capacity for 29 concerts in the new, 2,000-seat hall, and 81% for seven shows at the 756-seat Irvine Barclay Theatre.”