INSTALLATION PROCESS XOOPS CORE 2.3.3 (htdocs/install/index.php)

Warning: Cannot modify header information - headers already sent by (output started at …/www/site.com/folder/htdocs/mainfile.php:22) in …/www/site.com/folder/htdocs/install/class/installwizard.php on line 87

Warning: Cannot modify header information - headers already sent by (output started at …/www/site.com/folder/htdocs/mainfile.php:22) in …/www/site.com/folder/htdocs/install/class/installwizard.php on line 88

Warning: Cannot modify header information - headers already sent by (output started at …/www/site.com/folder/htdocs/mainfile.php:22) in …/www/site.com/folder/htdocs/install/page_langselect.php on line 33

Warning: Cannot modify header information - headers already sent by (output started at …/www/site.com/folder/htdocs/mainfile.php:22) in …/www/site.com/folder/htdocs/install/page_langselect.php on line 36

Warning: Cannot modify header information - headers already sent by (output started at …/www/site.com/folder/htdocs/mainfile.php:22) in …/www/site.com/folder/htdocs/install/class/installwizard.php on line 204

Warning: Cannot modify header information - headers already sent by (output started at …/www/site.com/folder/htdocs/mainfile.php:22) in
…/www/site.com/folder/htdocs/install/class/installwizard.php on line 206


SOLUTIONS?
Thanks!

Did you modify any files manually?

When googled for your error, I found following tip

I'm sorry, I have uploaded again all XOOPS Core 2.3.3 and now all goes well.
Thank you all.

I'm glad that everything worked out!

Welcome to XOOPS!!!

thank you very much