I am running a mixed logit model using 'mlogit' for a choice experiement data of 866 respondents for a dependent variable choice and 4 independent variables as seen-price bt qr antibio. Following is the code and errors.

RCEchoice.mxl <- mlogit(CHOICE ~ price + bt + qr + antibio

,rpar = c(bt= 'n', qr = 'n'

, antibio= 'n')

, data=dbchoice.data

, reflevel = "3"

,correlation = TRUE, halton = TRUE,

R = 10)

summary(RCEchoice.mxl)

Error: Error: $ operator is invalid for atomic vectors

Warning messages:

1: In if (n >= 10000L) return(TRUE) :

the condition has length > 1 and only the first element will be used

2: In if (n >= 10000L) return(TRUE) :

the condition has length > 1 and only the first element will be used

3: In if (n >= 10000L) return(TRUE) :

the condition has length > 1 and only the first element will be used

4: In if (n >= 10000L) return(TRUE) :

the condition has length > 1 and only the first element will be used

5: In if (n >= 10000L) return(TRUE) :

the condition has length > 1 and only the first element will be used

6: In if (n >= 10000L) return(TRUE) :

the condition has length > 1 and only the first element will be used