[Gretl-users] maximum like. conditions

I'm working with different GARCH models and I trying to determine parameters. For test case I took example from user guide and applied restirction to the parameters as stated in user manual, code is in the end of the mail. All I get is: Syntax error in command line Error executing script: halting What am I doing wrong ? Thanks, Davor open djclose series y = 100*ldiff(djclose) scalar mu = 0.0 scalar omega = 1 scalar alpha = 0.4 scalar beta = 0.0 mle ll = check ? (-0.5*(log(h) + (e^2)/h)) : NA series e = y - mu series h = var(y) series h = omega + alpha*(e(-1))^2 + beta*h(-1) scalar check = (alpha>0) & (beta>0) params mu omega alpha beta end mle