This is probably supposed to be in the Wordpress forums, but I thought it belonged here. 
I have a WP blog. I’ve added the unity plugin, with no errors. Then…
I try to upload a .unity3d file to the media library. Result:
"Game.unity3d” has failed to upload due to an error
File type does not meet security guidelines. Try another.
What’s the problem? Does Wordpress not support unity3d files or what?
NOTE: I’m running the latest version of Wordpress.
Did you ever find a solution for this ?
No, but I think that I need to add a #define() to my WP_config.php I just don’t know what to put in the brackets.
Sorry for the very late reply. 
I have found an answer now. 
It’s called…
FTP.
Just use an FTP tool to upload the files to the current month’s upload folder. Then follow the instructions as included in the download.
I recommend Cyberduck as an FTP tool.
You don’t need any software, windows will do that for you. Go to My Computer, click on the address bar on top where it says Computer. Delete all that and type ftp://www.yoursite.com. It’ll ask you your username and password and just enable the save checkbox at the bottom. Now you can transfer files like you normaly would in windows.
– Edit – Sorry, didn’t notice how old the last post was.