I get several error activating the module

[pcha]

When I activate de plugin and save the settings I the next error list:

Warning: include(tax_rates/ar.php): failed to open stream: No such file or directory in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 72

Warning: include(tax_rates/ar.php): failed to open stream: No such file or directory in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 72

Warning: include(): Failed opening 'tax_rates/ar.php' for inclusion (include_path='.:/opt/php7/lib/php') in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 72

Notice: Undefined variable: declared_rates in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 94

Warning: Invalid argument supplied for foreach() in {my_wp_url}/wp-includes/class-wp-list-util.php on line 148

Warning: Invalid argument supplied for foreach() in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 96

Notice: Undefined variable: declared_rates in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 104

Warning: Invalid argument supplied for foreach() in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 104

Warning: array_map(): Argument #2 should be an array in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 121

Warning: implode(): Invalid arguments passed in {my_wp_url}/wp-content/plugins/doliwoo-develop/includes/class-wc-tax.php on line 122

Notice: Trying to get property of non-object in {my_wp_url}/wp-content/plugins/doliwoo-develop/doliwoo.php on line 214

These are my settings:

Thanks in advance!