I am not being able to change my cursor

My current cursor theme is oxygen, and I am trying to change it to some other theme. But unfortunately, I am not being able to do so. I have installed gcursor, and other cursor themes like mobility and crystal. Then, I select the preferred theme using gcursor, but the changes are not getting updated. Infact, I am also not able to install new cursor themes, for the Install New Theme button is not responding properly.