access assigned objects

Dear list,
I am trying to write a function that will make a matrix of each row of a data frame (4 columns), calculate a fisher.test on each resulting matrix and assign a vector of the p-values.  I have gotten through making the matrices,  but cannot calculate the fisher.test.
 
fm<-function(x)
{dfrow<-nrow(x)
 
mm <- vector("list", dfrow)
for(i in 1:dfrow)
   mm[[i]] <- matrix(x[i,],nr=2)

}
 
I don't know how to access each mm[[i]] as everything I've tried gives me the error that 
"Error in fisher.test(mm[[i]]) : all entries of x must be nonnegative and finite"
 
All the numbers in the matrices are between 1 and 600.  
 
 
Thanks,
Beth



	[[alternative HTML version deleted]]