Error in LINEQS

#1
I'm trying out the PROC CALIS LINEQS example from here using the Wheaton dataset (it works using the PATH and RAM examples), but when I use this code:


Code:
proc calis nobs=932 data=Wheaton;
   lineqs
      Anomie67     = 1.0    * f_Alien67 + E1,
      Powerless67  = 0.833  * f_Alien67 + E2,
      Anomie71     = 1.0    * f_Alien71 + E3,
      Powerless71  = 0.833  * f_Alien71 + E4,
      Education    = 1.0    * f_SES     + E5,
      SEI          = lambda * f_SES     + E6,
      f_Alien67    = gamma1 * f_SES     + D1,
      f_Alien71    = gamma2 * f_SES     + beta * Alien67 + D2;
   std
      E1           = theta1,
      E2           = theta2,
      E3           = theta1,
      E4           = theta2,
      E5           = theta3,
      E6           = theta4,
      D1           = psi1,
      D2           = psi2,
      f_SES        = phi;
   cov
      E1  E3       = theta5,
      E2  E4       = theta5;
run;
it generates this error:
"Predictor variable Alien67 in the equation with outcome variable f_Alien71 is neither a manifest, an F, an E, nor a D variable."
What am I doing wrong?