It won't create a directory to install any Plug ins

Have had to start from scratch with all my plug ins but
it now won’t let me install any as it says it cannot create
directory:

Downloading install package from http://downloads.wordpress.org/plugin/mappress-google-maps-for-wordpress.1.5.8.10.zip…

Unpacking the package…

Installing the plugin…

Could not create directory. /nfs/c01/h05/mnt/34648/domains/transitionheathrow.com/html/wp-content/plugins/mappress-google-maps-for-wordpress/

Plugin install failed.

Any help would be much appreciated?