[R] problem with HoltWinters

[Luis Miguel Almeida da Silva]

Dear helpers
 
I'm having a problem with function HoltWinters from package ts. I have a time series that I want to fit an Holt-Winters model and make predictions for the next values. I've already built an object of class ts to serve as input to HoltWinters. But then I get an error; I've used HoltWinters a lot of times and this never hapened
 
> data.HW<-HoltWinters(data.ts)
Error in model.frame(formula, rownames, variables, varnames, extras, extranames,  : 
        variable lengths differ
 
This is the data

> data.ts
         Jan     Feb     Mar     Apr     May     Jun     Jul     Aug     Sep
2001 1117001 1017287 1195142 1049729 1409147 1267002 1579907 1563127 1195597
2002 1228333 1062520 1080117 1171998 1383951 1141008 1604061 1446024 1276017
2003 1068221 1045052 1164273 1091765 1272330 1305676                        
         Oct     Nov     Dec
2001 1290688 1104137 1027022
2002 1262232 1048522 1174157
2003                        
 
Do you know what is happening?
 
Thank you
Luis