how to Calculate Stress Intensity Factor

hi ... i am doing multiple crack analysis using ANSYS. i m using a circular disc having dia of 200 mm , thickness 6 mm and two parallal cracks of 30 mm at centre...cracks are seperated by a distance of 5 mm...plese tell me how i can find the Stress Intensity Factor at the crack tip... i have followed all the steps given in ANSYS help..but still i did not get the results.....there are an error which is "The crack face is not parallal to currently active x axis"...plese help me how to solve this problem..