more statcounter Qs

I have been reading the posts about installing StatCounter. I have enable the W3C or whatever it is, and am trying to copy and paste into the footer right above the </body> line but it is giving me warnings…

Warning: fopen(D:\clients\17671\betweenthehashes.com\betweenthehashes.com/wp-content/themes/classic/footer.php) [function.fopen]: failed to open stream: Permission denied in D:\clients\17671\betweenthehashes.com\betweenthehashes.com\wp-admin\theme-editor.php on line 58

Warning: fwrite(): supplied argument is not a valid stream resource in D:\clients\17671\betweenthehashes.com\betweenthehashes.com\wp-admin\theme-editor.php on line 59

Warning: fclose(): supplied argument is not a valid stream resource in D:\clients\17671\betweenthehashes.com\betweenthehashes.com\wp-admin\theme-editor.php on line 60

Warning: Cannot modify header information – headers already sent by (output started at D:\clients\17671\betweenthehashes.com\betweenthehashes.com\wp-admin\theme-editor.php:58) in D:\clients\17671\betweenthehashes.com\betweenthehashes.com\wp-includes\pluggable-functions.php on line 270

Sorry if that is too busy. What else do i have to do?

thanks for your help.