按以下形式输入方程组,进行seemingly Unrelated Regression估计,EVivews总是提示"Near singular matrix",到底哪里错了?请高手不吝赐教.

w1=C(1)+C(2)*p1+C(3)*p2+C(4)*p3+C(5)*p4+C(6)*p5+C(7)*p6+C(8)*p7+C(9)*u

w2=C(10)+C(11)*p1+C(12)*p2+C(13)*p3+C(14)*p4+C(15)*p5+C(16)*p6+C(17)*p7+C(18)*u

w3=C(19)+C(20)*p1+C(21)*p2+C(22)*p3+C(23)*p4+C(24)*p5+C(25)*p6+C(26)*p7+C(27)*u

w4=C(28)+C(29)*p1+C(30)*p2+C(31)*p3+C(32)*p4+C(33)*p5+C(34)*p6+C(35)*p7+C(36)*u

w5=C(37)+C(38)*p1+C(39)*p2+C(40)*p3+C(41)*p4+C(42)*p5+C(43)*p6+C(44)*p7+C(45)*u

w6=C(46)+C(47)*p1+C(48)*p2+C(49)*p3+C(50)*p4+C(51)*p5+C(52)*p6+C(53)*p7+C(54)*u