Hi dgmdonna,
Unfortunately, that’s a generic error message and doesn’t provide insight into the issue you’re facing. You should have received an error message from WordPress with more information. If you did, can you please provide me with a copy of the error message present in the email?
If you didn’t receive the email (which can happen so don’t worry if this happens), please edit your wp-config.php file and find:
/* That's all, stop editing! Happy publishing. */
Add to the previous line:
define( 'WP_DEBUG', true );
define( 'WP_DISABLE_FATAL_ERROR_HANDLER', true );
This will allow WordPress to show error messages rather than hiding them. Once enabled, please attempt to install/activate the theme again.
Kind regards,
Alex