Could not open handle for fopen()

I am getting the failures when WP or plugin code tries to use fopen().

I DO have
allow_url_fopen = On
in every php.ini file that the locate command can find. Any thoughts?

I am using an old version of PHP and Apache (but allowed by WP minimum requiremens) on an old CentOS 4.3 box. Can’t really upgrade it unfortunately.

Any thoughts? I can use the core control plugin to switch the core to use fsockopen(), which work for WP core, but lots of plugins still fail…