Error: Invalid grouping factor specification
<p>I am trying to use <code>glmer</code> to model coral recruitment and get the error "Error: Invalid grouping factor specification, Site" when I run the model after re-scaling the variables. Help greatly appreciated</p>

<pre><code>m1&lt;-glmer(Tot~cs.Tile(Tile)+cs.Coral_T(Coral_T)+cs.Sponge(Sponge)+
cs.Turf(Turf)+cs.Acro(Acro)+cs.Por(Por)+cs.Poc(Poc)+
cs.Mer(Mer)+cs.Agar(Agar)+cs.Fav(Fav)+
cs.Den(Den)+cs.Sid(Sid)+cs.CCA(CCA)+cs.Soft(Soft)+
  (1|Site), 
family=poisson, data=data)
</code></pre>

<p>I have 16 variables and 368 obs:</p>

<pre><code>str(data)
'data.frame':   368 obs. of  16 variables:
 $ Site   : Factor w/ 25 levels "Eight","Eighteen",..: 10 10 10 10 10 10 10 10 10 10 ...
 $ Tile   : int  1 2 3 4 5 6 7 8 9 10 ...
 $ Tot    : int  28 24 17 13 29 19 6 13 14 4 ...
 $ Coral_T: num  32.6 32.6 32.6 32.6 32.6 ...
 $ Sponge : num  0.206 0.206 0.206 0.206 0.206 ...
 $ Turf   : num  32.3 32.3 32.3 32.3 32.3 ...
 $ Acro   : num  3.45 3.45 3.45 3.45 3.45 ...
 $ Por    : num  1.15 1.15 1.15 1.15 1.15 ...
 $ Poc    : num  0 0 0 0 0 0 0 0 0 0 ...
 $ Mer    : num  0.175 0.175 0.175 0.175 0.175 0.175 0.175 0.175 0.175 0.175 ...
 $ Agar   : num  24.2 24.2 24.2 24.2 24.2 ...
 $ Fav    : num  1.02 1.02 1.02 1.02 1.02 ...
 $ Den    : num  1.18 1.18 1.18 1.18 1.18 ...
 $ Sid    : int  0 0 0 0 0 0 0 0 0 0 ...
 $ CCA    : num  0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 ...
 $ Soft   : num  0 0 0 0 0 0 0 0 0 0 ...
</code></pre>