R help - May 2008 - Error in FUN(newX[, i], ...) : no complete element pairs in R 2.7.0 patched

Using R 2.6.0 patched I was able to calculate the variance of each row
of a matrix without error, even if some rows had only NAs.  I would just
get NAs back as the variance for those rows.  Now with R 2.7.0 patched I
get an error "no complete element pairs" if any one row has all NAs.
Can anyone tell if I can make R 2.7.0 patched behave as R 2.6.0 did so I
don't have to change all my code.  Or maybe suggest a simple work
around. A short example is below.  Thanks in advance. 

dat <- data.frame(aa=c(1,2,as.numeric('NA'),4),
bb=c(2,3,as.numeric('NA'),5), cc=c(3,4,as.numeric('NA'),6),
dd=c(4,5,as.numeric('NA'),7))
apply(dat, 1, var, na.rm=TRUE)

> dat
  aa bb cc dd
1  1  2  3  4
2  2  3  4  5
3 NA NA NA NA
4  4  5  6  7
> apply(dat, 1, var, na.rm=TRUE)
Error in FUN(newX[, i], ...) : no complete element pairs
> 
> 
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