[R] help with lmer,

[Brendan Connors]

Hi R-users:

New to R and I am trying to run a GLM with random effects.

I have 3 replicates ('Replicate) of counts of parasites ('nor.tot.lep') 
before and after an experiment ('In.Out'). When I run lmer I get the 
error messages (16 of each) below...

 > lmer(nor.tot.lep ~ In.Out + (In.Out|Replicate),data=coho, family 
=tweedie(var.power = 1,
+ link.power = 1))
Generalized linear mixed model fit using PQL
Formula: nor.tot.lep ~ In.Out + (In.Out | Replicate)
Data: coho
Family: Tweedie(mu^1 link)
AIC BIC logLik deviance
849.2 867.4 -419.6 839.2
Random effects:
Groups Name Variance Std.Dev. Corr
Replicate (Intercept) 0.78861 0.88804
In.Out 0.67232 0.81995 -1.000
Residual 2.96308 1.72136
number of obs: 279, groups: Replicate, 3

Fixed effects:
Estimate Std. Error t value
(Intercept) -0.2431 0.6619 -0.3672
In.Out 1.6004 0.5645 2.8349

Correlation of Fixed Effects:
(Intr)
In.Out -0.975
There were 30 warnings (use warnings() to see them)

 > warnings()
Warning messages:
1: Estimated variance-covariance for factor ‘Replicate’ is singular
in: LMEopt(x = mer, value = cv)
2: nlminb returned message false convergence (8)
in: LMEopt(x = mer, value = cv)

I have made sure I have the latest lme4 version, any help would be much 
appreciated.

Cheers,

Brendan Connors
Behavioural Ecology Research Group