大白菜2012 发表于 2012-10-16 05:21 
if you "set trace on", you will find out some hints of your problem.
thx a lot. I've found where the problem is. It seems that something is wrong with " forvalues i=1(1)r(max)". But I have no idea of how to correct it .
Could you please kindly help me figure it out ?
Thank you very much!