[R] Object not Found Error on a .csv file

[Valerie Shalin]

Hello:

I am a new user, running the latest version of R on my Mac.  I have started by reading a file with the read.csv command:
task2analyses <- read.csv(file="GroupsWithRTsEqualN.csv",head=TRUE,sep=",")

When I print it out in R, the file appears to be intact, with the proper headers.  Yet, when I run test commands like the following:
> cor(GfullUA,GFullUA) 

I get back a message Error in is.data.frame(y) : object 'GFullUA' not found

This is not the case for all of the variables in the file.  Some can be tested with is.numeric (or character). And some are read
properly when I test the summary command.  

I have looked on Google, and have been unsuccessful in searching documentation.

Thanks for any help,

Valerie Shalin