i have a blank page when accesing user.php on my site

refering to this faq

https://xoops.org/modules/smartfaq/faq.php?faqid=338

i've checked my main.php and i indeed have blank lines in my mainfile.php after the closing ?>

i had the user.php blank page problem before..and i managed to fixed by removing the blank lines from mainfile.php
as suggested in the faq but suddenly now i can't remove the blank lines from mainfile.php

i set mainfile.php permission to 777 remove the blank line thru cpanel file manager then save...chmod 444 but the blank line is still there in mainfile.php

i also tried upload a new mainfile.php (without blank lines in the end) thru cpanel file manager n also thru my ftp
program..successful upload but when i check there are blank lines after the closing ?> in mainfile.php

also tried to clear browser cookies n XOOPS template_c but still the blank lines still exist

how do i fix this ?

get your webhost to check it out - could be they are stopping you from making chmod changes??? Seen similar issues with those sorts of file permissions before. (BTW I have C panel but do eveything related to files through ftp - a much easier and faster way to make changes)