Themes Will Not Install-see Error Message and Details Below

Name: Richard Yanni

Email: professoryanni@gmail.com

Subject: Themes will not install

Message: When I try to install several of your themes, this is the
same message that I get:

"Installing Theme from uploaded file:
148751_wpmu-dev-dashboard-3.2.5.zip
Unpacking the package

Installing the theme

The package could not be installed. The theme is missing the style.css
stylesheet.

Theme install failed."

Can you please tell me what to do, I am on a deadline and counted on
the reliability of your products.

I have installed the latest version of WordPress as prompted to by WP
when I logged in. The other theme that failed was:

"Installing Theme from uploaded file: 148751_membership-3.4.2.zip
Unpacking the package

Installing the theme

The package could not be installed. The theme is missing the style.css
stylesheet.

Theme install failed."

If someone in the community is able to assist me, I would be grateful for the help.

Thanks,
Richard