[R] error in summary.Design

[DAVID ARTETA GARCIA]

Dear list,

after fitting an lrm with the Design package (stored as "mymodel") I  
try running a summary, but I get the following error:

dim(mydata)
[1] 235   9

names(mydata)
  [1] "id"   "VAR1" "VAR2" "VAR3" "VAR4" "VAR5" "VAR6"  "VAR7" "VAR8"

summary(mymodel)
Error in `contrasts<-`(`*tmp*`, value = "contr.treatment") :
   contrasts can be applied only to factors with 2 or more levels

but,

VAR1 is my dependent
> nlevels(factor(VAR1))
[1] 2

VAR2 is continuous
> summary(psa)
    Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
    0.90    6.05    8.40   10.99   13.15   59.70

and for the remaining variables...

> nlevels(factor(VAR3))
[1] 2
> nlevels(factor(VAR4))
[1] 2
> nlevels(factor(VAR5))
[1] 3
> nlevels(factor(VAR6))
[1] 2
> nlevels(factor(VAR7))
[1] 2
> nlevels(factor(VAR8))
[1] 2


What I am missing?

Thanks in advance,

David