Cannot redeclare

When I’m activating a parent theme developed off of the 2010 theme, I get a 500 error. This isn’t happening when I try to activate child themes based off of the theme I’m attempting to activate. I thought it might be a problem w/ one of the themes, but when I researched online it said this is often due to either a problem with the .htaccess file, or not enough memory on the php.ini file.

Here is the error message that is generated in the logs:

Cannot redeclare missouristate2010_excerpt_length() (previously declared in D:\\Inetpub\\BlogsTest.MissouriState.edu\\wp-content\\themes\\MissouriState2010\\functions.php:200) in D:\\Inetpub\\BlogsTest.MissouriState.edu\\wp-content\\themes\\MissouriState2010\\functions.php on line 202, referer:https://blogstest.missouristate.edu/wp-admin/themes.php?activated=true

Here is the content of the .htaccess file:

RewriteEngine On
RewriteBase /

#uploaded files
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*
RewriteRule ^(.*/)?files/(.*) wp-content/blogs.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteCond %{REQUEST_URI} ^.*/wp-admin$
RewriteRule ^(.+)$ $1/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule . - [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-.*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

<IfModule mod_security.c>
<Files async-upload.php>
SecFilterEngine Off
SecFilterScanPOST Off
</Files>
</IfModule>

Thank you for any help.