Hi Paulo

This could be a file permission error - can you check the php.ini file and the  upload_tmp_dir setting making sure the folder exists and the folder has write permissions.

if this doesn't help there could be a problem with the file size limit being exceeded

1. Go to [Course name] > Course administration > Edit settings and obtain the Maximum upload size value under Files and uploads.
2. Check the size of the file matches the course upload limit.
3. Go to Quick-access menu > Server > PHP Info and check values for:
   
   • post_max_size
   • upload_max_filesize (this can be changed by editing the php.ini file located on the web server e.g. upload_max_filesize = 60M will increase max file upload to 60mb)
   • max_execution_time - (a low execution time can impact the uploads of larger files, particularly if you also have poor bandwidth)

The first two will normally determine the site upload limit, so they're worth checking, especially if the limit needs to be raised.

• Check that no restrictions have been set on the webserver:
  
  • If the webserver is Apache, it's worth checking to see if there is an .htaccess file with upload limits in place. This would normally show the appropriate limit via the user interface, so if the file is within the limit shown in the user interface, it's unlikely to be related to .htaccess.
  • If the webserver is IIS, there could be a filesize limit in IIS request filtering.
• Check to see if a proxy server is being used. There could be an upload limit set on the proxy server.