Writing to a file

["Chris Evans" <evanscje@xxxxxxxxxxxxx>]

I'm trying to make a txt file that has a single column showing my currentposition which should be the number of contracts I am long or short each day.
I wrote:
FileAppend("C:\filename.txt",Numtostr(Currentcontracts,0) + Newline);

This is clearly not working  .. can anyone help correct my syntax?
thanks 

CJE