Actually, there are at least three different server side sets of limitations that could impact file transfers.
You can set limitations via your webserver (Apache, for example) and Apache has always been subject to absolute limitations based on your file systems limitations.
The limit most often discussed in the forums is a limit imposed via your php configuration. php is a scripting language that sits on top of the webserver. There is a general upload limit and a post limit which are discussed in the forum elsewhere, e.g.
upload_max_filesize = 83886080
post_max_size = 83886080
Here is a quick discussion of these items: http://www.radinks.com/upload/config.php
You can also set limits using Moodle. While a layering analogy is not altogether accurate, Moodle employs php and you can think of it as the next layer. Course by course max file upload can be set and you can look here for explanation: http://docs.moodle.org/en/Course_settings#Maximum_upload_size
Each subsequent layer cannot make max transfers larger, but they can make them smaller.
thanks for your help it worked