I had the same issue before when I used to transfer big files through a cable, although I never had a problem creating a folder on my tablet through my desktop. Setting the tablet screen to never turn off fixed the problem for me.
You might also install Kies, just so that it installs the most recent driver into Windows for the tablet (not sure if theres a Mac version). I would not however, suggest using Kies to manage files between your computer and tablet. It's a very badly written piece of software and has a lot of issues and crashes a lot(more that any other program I have). I only use it to make sure my driver is up to date, and for firmware updates for android. When the JB update was released I tried for 3 days every hour or so to update but the server was always busy, so I ended up using Kies to update, which was a whole new set of problems(like I said Kies is terrible),
If you have to, you could always just pull the card out and put it in your computer or external card reader. I did that initially because when I first got the extsdcard there were a lot of files and it was just faster.
I now transfer files using cloud storage. I use Dropbox, SkyDrive, Box.net, and Google Drive. I also use Foldersync to sync the files from the cloud to locally stored folders on my tablet and phone. You could then always save files to the Dropbox folder on your computer(or place them there) which would then automatically upload to the cloud, then folder sync would copy the file from the cloud to a folder on your tablet. I have it so that my tablet, phone, and desktop are always in-sync without having to do anything. Plus I have it so that if I take a photo with either my phone or tablet it will automatically be sent to the gallery of the other device so that my photo gallery is updated on either device and also sent to my desktop for backup. You'll need Foldersync (there's a paid and free version) to do it automatically, other wise you'll have to manually download the files from whatever cloud storage you are using. You would of coarse need to have internet access on the tablet for this to happen. I also use Solid Explorer(I think they got rid of the free version) on both my android devices. It not only can access my cloud storage accounts but has a split window(makes it easy to move and copy files from one folder to another) in landscape mode, and you have the ability to drag and drop to copy or move files.
I tried using Airdroid and a handful of other wifi solutions but I had issues with some files that would cause crashes or would always fail to transfer.
Hope that helps, good luck.