R help - Jul 2006 - Discretize data.frame

Dear useRs,

I use dics.ef function from dprep package to discretize continuous 
variable using intervals of equal frequencies. Dataset to be discretized 
include 4 continuous and 2 discrete variables in the following order:

Continuous Countinuous Countinuous Discrete Discrete Continuous

The problem emerge when I try to discretize the last continuos variable:

library(dprep)
dics.ef(my.dataframe, 1:6,5) ## all 6 variables in data.frame

I have no further idea why the function above don't work on the last 
variable in dataframe.

Thanks in advance for any further notes,

Andrej