New Line in my WP-Config Messing Up Visual Editor

I have been having problems with my post editor not getting out of html mode. I have traced the problem down to a new line I added into my WP-Config file to disable php file compression and enable WP Super Cache.
Here is the new line: ini_set(‘zlib.output_compression’, 0);. I have placed it in the top of the WP-Config file and I have also tried placing it in other places in the file. It works for enabling the Super Cache but always messes up my post editor.
How can I get the Super Cache working right and have my post editor working in visual mode again?