Well, your online research is very helpful. To give you some insight on the extension, when the download process is initiated there is a PHP setting that gets called:
This should effectively stop PHP from timing out the script. In theory, PHP should continue to run the script without a time limit.
Now, you have stated that you are already diddling with time limit settings and the process is still timing out. The curious thing is that there is no error message. If it were PHP shutting the process off, there should be an error message.
The second answer from the bottom (by Hendy Irawan) on the stackoverflow.com site (http://stackoverflow.com/questions/2084 ... -no-errors
) is the most compelling answer. If you are on a shared hosting site, your host may very well have a program that terminates zombie processes after a set period of time. A zombie process is a term that means any computer program that is mindlessly running in the background using up system resources and not accomplishing anything. So, the host may have a zombie process termination program that is mistaking your download script as a zombie process.
I highly recommend that you check with your host's tech support. They will be able to verify this and/or provide additional information about the server. This additional information may provide the key to understanding what is happening here. Put it to them simply. Let them know you are running a download script in PHP. It is a proven mature script and runs successfully on other servers. But when you try to download large files over long periods of time on this server, the process always gets terminated early. Ask them if they why they think this might be happening and ask them if they think it might be due to any zombie process termination program they might be running.
~ Best regards