[R-sig-ME] Error en mer_finalize(ans) : Downdated X'X is not positive definite, 1. What is wrong with my model?

[Ben Bolker]

PALACIO BLASCO, SARA <s.palacio at ...> writes:

[snip]

> I am trying to run the following model in glmer:
> 
> > M_bud_type1=glmer(Dead~Treatment* fBud_type + fBud_type:Species +  
> > (1|fRep), family=binomial, data=species)
> 
> where:
> - Dead is a binomial response variable
> - fBud_type is a fixed factor with 3 levels
> - Species is a fixed factor with 9 levels nested within fBud_type and
> - fRep is a random factor with 27 levels nested within Species
> 
> I have 1386 observations.
> The error message I receive reads:
> 
> Error en mer_finalize(ans) : Downdated X'X is not positive definite, 1.
> 

  Did you already read the http://glmm.wikidot.com/faq#errors section?

  It sounds like all your predictors are categorical (although we don't
know about Treatment), so centering isn't really as important/as practical
an option (you can use sum-to-zero contrasts, but it probably won't
make a big difference).

  Ben Bolker