Error with a sparse files

Hello, help me please.

I have a Fedora 22 and KVM. I am install worksation and Gateway on this istruction Whonix ™ for KVM
But i want put the image on trucrypt container (100GB). I am edit .xml - var/libvirt/images/ to /media/truecrypt/
But when i move file wiht command:
sudo cp --sparse=always Whonix-Gateway*.qcow2 /media/truecrypt/Whonix-Gateway.qcow2
I have a error
cp: error writing “/media/truecrypt7/Whonix-Gateway.qcow2”: the File is too big
(error translate with other language)

Why do I have this problem? the actual size of not more 100GB

What file system are you using within the container? One that supports sparse files such as ext4?