[R] question on lmList

[eugen pircalabelu]

Hi list,

Using the lmList function from “nlme package” I get the following error message: 

“Error in !unlist(lapply(sum.lst, is.null)) : invalid argument type”

#  this is the syntax used
#  fm_cream <-lmList(MULTDV~TIME|cod, data=zz, na.action=na.omit)
#  summary(fm_cream)

When I generate a simple example the function works, but on the real data I get that message. I imagine that it is a common message when data is misused, but I don’t know where the problem could be. Has anyone encountered this message and what does it mean exactly? Is there a “guide” or something more detailed about the general error messages from different packages, somewhere?

Thank you very much and have a great day ahead!

Eugen Pircalabelu