@wpyogi thanks for your answer.
The theme purchaser didn’t want to give up. He sent email the the developer for help but no reply after 1 week.
Well.. If I can’t figure out how to make this button work then perhaps I got to convince him to buy another one.
I’m facing this exact problem. Did anyone have a chance knowing a solution?
I was so panicked just now because I couldn’t log in to http://www.wpos.pro dashboard and found in my error.log
“PHP message: PHP Fatal error: print_r(): Cannot use output buffering in output buffering display handlers in /wp-content/plugins/wp-super-cache/wp-cache-phase2.php on line 253” while reading upstream
Found this post and upgrading to WP-Super-Cahce 1.4.4 solved my problem. Thanks.