Hi Dan,

from #9 in the INSTALL.txt

9. Setting PHP variables
   There are some PHP configuration variables that may need to be customised, depending on your needs. The variables that are commonly changed
   include "memory_limit", "upload_max_filesize", "post_max_size", "max_input_vars" and "upload_tmp_dir".

   memory_limit - This will need to be increased for restoring large course backups or unzipping large files within Totara
   upload_max_filesize - This setting in conjuction with "post_max_size" will determine how high you can set the max upload size within Totara
   max_input_vars - This setting will need to be increased to a minimum of 2000 if you would like to customise any of the Totara language packs.
   upload_tmp_dir - Some customers may wish to enable this setting and specifically set a directory where files are temporarily stored during the upload process. Note the web server user must have permissions to write files in this directory, or all file uploads will fail.

As your SCORM files are so large then I would check that all of memory_limit, upload_max_filesize and post_max_size are at least 400Mb otherwise there is no way the server will accept such large SCORMS.

Once the PHP variables have been set and the webserver restarted, you should also check Site Admin -> Courses -> Course Default Settings -> Maximum upload size setting to ensure it is also set to a value large enough to accommodate your large SCORM files.