今天学习张晓桐的Eviews编程，按照书上的实例编写，在Eviews中运行却出现错误，
具体语句如下（是关于结构性突变下的ADF检验中的均值变动循序检验一法）
workfile uroot a 1950 2003
series im
im.fill 21.40,31.46,33.54,39.88,37.79,51.13,44.35,41.22,50.74,58.03,51.75,29.25,22.15,24.86,30.44,41.08,45.53,40.09,38.18,35.81,42.66,40.15,49.16,79.08,116.02,111.75,97.73,98.37,137.90,175.25,203.40,244.48,233.20,271.08,387.81,722.46,811.65,815.25,875.63,795.91,911.90,1170.35,1452.06,1728.12,2362.45,2283.14,2251.15,2281.45,2306.31,2809.10,3870.22,4220.22,5180.30,7253.41
series lnim=log(im)
show lnim.line
series se1cv15=-4.80
series sequen1
equation eqsequ1
for li=9 to 48
series d1=0
smpl 1950+li 2003
  d1=1
smpl @all
eqsequ1.ls d(lnim) lnim(-1) d(lnim(-1)) c @trend
sequen1(li)=eqsequ1 @tstats(1)
next
graph graph3.line sequen1 se1cv5
show graph3
运行之后说“for li=9 to 48”中 li 没有定义，请问应该怎么改？