[R-sig-ME] error message using glmmadmb

[RH Gibson]

I am trying to use glmmadmb to build a model.

Code used:

m1<-glmmadmb(spdiv~nsn*Insect.type+ara*Insect.type+rap*Insect.type+fsize+(1|Site),family="nbinom")

"Site" is a categorical variable and is a factor (non numeric).

I get the error message:

Error in eval(expr, envir, enclos) : could not find function "Droplevels"
In addition: Warning message:
In is.na(rows) : is.na() applied to non-(list or vector) of type 'NULL'

Can anyone tell me why I am getting this message, please?






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