I'm running DokuWiki on Windows 2003 (with Apache 2.0.59, PHP 220.127.116.11). I noticed that big file downloads didn't work. Download started, but after some time, the download broken. I found out that the max_execution_time in php.ini was 30 seconds, I set it to larger number, and the download was finished successfully.
I checked the fetch.php and found that there is a "@set_time_limit(); // large files can take a lot of time" line. I checked the PHP documentation and found that the zero value means that no time limit is imposed. I set back the max_time_limit to 30 in php.ini and wrote the zero value as parameter to set_time_limit(), and the download succeeded.
I mean zero value is needed for set_time_limit to disable timeout: "@set_time_limit(0); // large files can take a lot of time"