Theme installation failed

My client is running WordPress on a remote server. When I first tried to update the twentyten theme I got the following error “An error occurred while updating Twenty Ten: Could not create directory./wordpress/wp-content/themes/twentyten. On the server I see the twentyten folder but cannot open it.

I have created a new folder and have tried about 15 times to install a zip version of twenty ten and this is the message I get:

Unpacking the package…

Installing the theme…

Could not create directory. /wordpress/wp-content/themes/twentyten/

Theme install failed.

Thanks, for the assistance.