How bad is the pluggable.php problem??

Hello,

I have read most of the post about the pluggable issue. Apparently I found mine also having the error as the display below:

Warning: Cannot modify header information – headers already sent by (output started at /home/anvideo/public_html/demo/wp-content/plugins/setnofollow.php:170) in /home/anvideo/public_html/demo/wp-includes/pluggable.php on line 275

However, once I hit the back button and refresh, everything seems workiing okay. Even for plugins & themes activation.

Seems I couldn’t find any better solution to get rid of the error and my blog is running well. I want to hear from your opinion here (if you are well with the php & wordpress code), is it okay for me to run the blog with this. I am about to write in new post. Please advise.

You can come to see my test blog here: https://www.AllNicheVideo.com/demo/

Thank you for your opinion.

Steven Wong