0Kb file when downloading big attachments

[jordibabot]

Hi. I've been messing with all the vars in my server to allow downloading high sized files, so now I can upload up until 120M.

Well the upload works fine, but the problem comes when I try to download a big file from 56,99M

If the file weights 57M or more then the resulting downloadable file is 0Kb. If its below 57M the size is normal.

Proof:

First one: http://www.rocalba.es/index.php?controller=attachment&id_attachment=53

Second one:  http://www.rocalba.es/index.php?controller=attachment&id_attachment=55

What's happening here?? Thanks in advance
Prestashop version: 1.6.1.1