You can probably not upload files larger than about 300.00 MiB in size.

Alternatively, you can use a file you already uploaded (by SFTP or SCP) to the project's incoming directory (/var/lib/fusionforge/chroot/home/groups/mdptoolbox/incoming). This direct sftp:// link only works with some browsers, such as Konqueror.
Choose an already uploaded file:

No uploaded file available.