Ubuntu 10.04, as well as 11.10, supporting Unity, A BUG mixes cursor themes ?!
Nevertheless doing :
sudo gedit /usr/share/icons/default/index.theme
as suggested - does not help, because in
../icons/default/ directory only shortcut to your theme exists and Unity mix it with the default DMZ-White (black).
I am using oxygen theme, after installing it with package manager - type 'oxygen cursor' I did the following :
I have tried to copy under 'gksudo nautilus' all content of
../icons/oxy-white/* to the
../icons/default/ directory - and GREAT !!! ... after the restart it works PERFECTLY !!!
P.S. I am using LinuxMint 11 Katya / Ubuntu 11.10