[Limdep Nlogit List] Nested Logit Model on NLOGIT

[Meghna Chakraborty]

Hi,
I am trying to develop a nested logit model on NLOGIT with the following
code. I am getting the following error to begin with and also I am not sure
if I am defining the utility functions and the ivset correctly. Please
help.

NLOGIT
;Lhs=CRUCode2
;Choices=P03,I03,P47,I47
;Tree=ChAg47[0(P03,I03), 1(P47,I47)]
;Show Tree
;Model:
U(P03)=ONE + DrAg1629*DrAg1629 + DrAg3059*DrAg3059 + DrAgMT60*DrAgMT60 +
DrGnM*DrGnM + DrRcWht*DrRcWht + DrRcBlck*DrRcBlck + DrRcOth*DrRcOth/
U(I03)=ONE + DrAg1629*DrAg1629 + DrAg3059*DrAg3059 + DrAgMT60*DrAgMT60 +
DrGnM*DrGnM + DrRcWht*DrRcWht + DrRcBlck*DrRcBlck + DrRcOth*DrRcOth/
U(P47)=ONE + DrAg1629*DrAg1629 + DrAg3059*DrAg3059 + DrAgMT60*DrAgMT60 +
DrGnM*DrGnM + DrRcWht*DrRcWht + DrRcBlck*DrRcBlck + DrRcOth*DrRcOth/
U(I47)=ONE + DrAg1629*DrAg1629 + DrAg3059*DrAg3059 + DrAgMT60*DrAgMT60 +
DrGnM*DrGnM + DrRcWht*DrRcWht + DrRcBlck*DrRcBlck + DrRcOth*DrRcOth/
U(0)=U(P03)+U(I03)/
U(1)=U(P47)+U(I47)/
;ivset:(Tree) = [1] $

Error   1089: Could not interpret string; expected to find number.

Thank you very much!

Best regards
Meghna