One thing I have always heard but not yet encountered, is that brushes made in Photoshop can only be used in versions equal to or higher than the one they were created in. I'm running CS6 Extended and I have never had that problem or the error message. I really don't know if it's true or not.
Why don't you post one of the brush ABR files that won't load for you and I will see if I can get it to load on mine. Are you using a PC or a Mac?
One other thing is that I never load brushes through Photoshop. I always locate the file in my downloads folder, rename it, copy and paste the file in the brushes preset directory and then restart Ps..........I don't know if it makes a difference or not.
It does happen, not very often though. I have downloaded brushes before and have received that same error message. I didn't dig into the cause, I just accepted it and went to find something else that did work.
Here is the .abr file if someone wants to confirm that it's just my version and not a corrupt file. I found out how to get my others loaded. I went to open brush from the main user interface, when the brush preset screen came up I dragged them all to the desktop and then moved them into the folder uploading after each move. It worked but it's a pain in my ass lol. Either way I can brush again which is a plus. Don't ask me how I came up with that crazy scheme.
Tested your file on CC 2014 and CS6 Ext but same thing....not compatible.
(That was on two different machines too)
Looking at the file its only 1KB in size, (according to the ever-reliable windows explorer), and your post link says its only 197 bytes, so my guess is the file is corrupt.
It also has "Mac OS X" and "com.apple.quarantine" in the header....whether that makes any difference I dunno.
Seems to me that either the download was incomplete or the download was ok and the file is just poo.
Sorry to be the bearer of bad news.....you could always try downloading it again from somewhere more reliable.