Cannot create directories (Venue 7840).

Okay, lets try this a third time. This time on my Sager Laptop running Arch Linux. Unlike my DELL tablet, this doesn't crash.

I am trying to create a directory on the SD card in my Venue 7840, however I have been unable to do so due to permissions errors. I find this odd since it should be formated with FAT32. I first tried

cd /storage/sdcard1

mkdir HumbleBooks

in terminal, but failed due to permissions. I then tried in other locations which I assumed would be less likely to be protected. Again failure. I then tried locations that should be protector, and was rewarded with exactly what I expected -- failure. I then installed Cheetah Media's file manager and did the same with that, but each attempt only ended in failure.

How am I suppose to do this? I want to make a directory for my HumbleBundle music and another for books on the SD card, but I can't seem to.