[R] Error in if (rank) { : argument is not interpretable as logical

[Duarte Viana]

Hello all,

I am running the function "rda" of the vegan library, like I did many
times without having troubles, and I get the following error message:
"Error in if (rank) { : argument is not interpretable as logical".

I am just testing a response matrix against a single explanatory
matrix, which is the result of a model matrix with 4 dummy variables
(coding for a factor of 5 levels).

myrda<-rda(resp, expl)

When I change the response matrix, it goes well.

Does anyone know what might be happening?

Thanks,

Duarte