[Limdep Nlogit List] Help required on silly matter

[Yasir Ali]

Hello,

I am quite new to NLOGIT and trying to run MNL model.  While running the model, I am getting this error "Error 1003: A choice label appears more than once in the tree spec." I am unable to figure out that where is the issue? Either in the code for running MNL or in the data?
I have checked the data and in the time series data, only one choice is selected at one instance. Can anyone please help me to resolve this issue? Thank you.

Cheers,
Yasir