Media Uploader not working =(

Hi,
My hosting company recently upgraded to new servers, moving from cPanel to Plesk admins.

Everything works fine (as far as I am aware) except the media uploader within the Add Posts section says the upload directory is unwritable – Ive triple checked and it is writable, and so are it’s parent directories.

here is what I get:

Unable to create directory /httpdocs/wp-content/uploads/2009/06. Is its parent directory writable by the server?

Any ideas?

Thanks!