From .:Rapidleech Wiki:.
The basic requirement for Rapidleech is a working web server with PHP installed.
- safe_mode off
Well, safe_mode can be turned on but you will need some knowledge of PHP to customize and make some workarounds.
- fsockopen enabled
Check this through phpinfo(), if fsockopen is listed under disable_functions Rapidleech cannot work.
- allow_call_time_pass_reference On
This isn't strictly required, but it will produce annoying messages across the pages.
- allow_url_fopen On
- memory_limit larger than 32MB
Or you won't be able to download some large files
- cURL support enabled
This is required to check links
- output_buffering Off
This is required to show the progress bar during download, although there are workarounds even if this is turned on. See FAQ.