wordpress theme is not getting install properly

Hello everyone

I am facing problem in installing any wordpress theme having slider panels and flash contents.
I have tried many themes (Zinfolio, Liberation etc) but everytime error shown below occurs:

Following Error message occur:

Warning: fopen(/home2/bestseo5/public_html/wp-content/themes/hostbox/style.css) [function.fopen]: failed to open stream: No such file or directory in /home2/bestseo5/public_html/wp-includes/functions.php on line 3598

Warning: fread(): supplied argument is not a valid stream resource in /home2/bestseo5/public_html/wp-includes/functions.php on line 3601

Warning: fclose(): supplied argument is not a valid stream resource in /home2/bestseo5/public_html/wp-includes/functions.php on line 3604

Style sheet is missing.

Please help me in solving this problem.
I will be heartily thankful to you.

Aditya