Error Trying to Upload/Install Themes

I keep getting the following error message any time I try to install a new theme (or similar messages). This theme in particular won’t even activate because it says it’s broken. Any advice?
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Unpacking the package…

Installing the theme…

Theme installed successfully.

Warning: fopen(/home/thepracticalnerd/thepracticalnerd/wp-content/themes/leonid/style.css) [function.fopen]: failed to open stream: No such file or directory in /home/thepracticalnerd/thepracticalnerd/wp-includes/functions.php on line 4165

Warning: fread(): supplied argument is not a valid stream resource in /home/thepracticalnerd/thepracticalnerd/wp-includes/functions.php on line 4168

Warning: fclose(): supplied argument is not a valid stream resource in /home/thepracticalnerd/thepracticalnerd/wp-includes/functions.php on line 4171
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Thanks in advance!