plot.zoo warnings - ignore or look for problem?

I'm getting warnings when I plot a zoo object:

dts <- chron(rep("2007-09-10", 5), paste("00:0", 0:4, ":00", sep=""),

c("y-m-d", "h:m:s"))

dat.zoo <- zoo(1:5, dts)
plot(dat.zoo)

Warning messages:
1: In v[[perm[1]]] : partial match of 'm' to 'month'
2: In v[[perm[2]]] : partial match of 'd' to 'day'

The plot appears to be correct.

So, is this a warning I can ignore, or do I have something amiss?

R.version

_                                          
platform       i386-pc-mingw32                            
arch           i386                                       
os             mingw32                                    
system         i386, mingw32                              
status         Patched                                    
major          2                                          
minor          6.1                                        
year           2008                                       
month          01                                         
day            06                                         
svn rev        43890                                      
language       R                                          
version.string R version 2.6.1 Patched (2008-01-06 r43890)

I have v 1.4-2 of zoo, built for R v 2.7.0, but it doesn't say it
requires that version of R.
(I realize I am not up-to-date on the version, but running production
apps sometimes means we have to wait a bit to upgrade.)

David L. Reiner
Rho Trading Securities, LLC