On an OSCommerce site, I had recently removed some junk code that had been injected at the top of many of the files.
I was also updating the OSCommerce version at the same time. When attempting to log into the admin panel on the new version, I got the following error.
Warning: Cannot modify header information - headers already sent by (output started at /path/to/root/directory/admin/includes/classes/object_info.php:2) in /path/to/root/directory/admin/includes/functions/general.php on line 22
I did not see anything obviously wrong with either file.
I googled the issue and quickly came accross this forum post.
So I checked both files and quickly found that indeed, the first file had an extra line before the initial <?php tag.When I had removed the junk code that appeared before this, I failed to make sure that the first <?php was at the very beginning of the file.
Now I am able to login.
Thanks Google and OSCommerce forums!