[R] na.rm problem

[sonal at deepfoo.com]

hi,

i am a new member.

i am using R in finding correlation between two variables of unequal length.

when i use 

cor(x,y,na.rm=T,use="complete")

where x has observations from 1928 to 2006 & y has observations from 1950 to
2006. I used na.rm=T to use the "complete observations".  So missing values
should be handled by casewise deletion. But it gives me error

Error in cov(close, close1, na.rm = T, use = "complete") : 
        unused argument(s) (na.rm ...)


Please help me with this as I am new to R.

Thanks,
Sonal