You have changed the Apache settings too, yes? You didn't mention it so I thought I'd check.
Next question - do you *really* want to load 15-18Meg video files into Moodle? Are you *sure* you don't want to set up a proper streaming server (and there are open-source options available - for example www.videolan.org) and simply put links to the material in Moodle. Slightly more cumbersome but on the other hand it might work
Installing and upgrading help
Problems uploading large files
This discussion has been locked so you can no longer reply to it.