Showing “no data for USD” In exchange rate column

Hi,

Since last update plugin settings starts showing bugs, when i set my default currency to AED and try to update exchange rate of other currency (USD) it shows “no data for USD” In exchange rate column.

Also in my dashboard there are 2 error from the plugin.
Warning 1 :
Warning: mail(/var/log/php_maillog): failed to open stream: Permission denied in /home/canariwa/public_html/Woo/wp-content/plugins/woocommerce-currency-switcher/classes/woocs_after_33.php on line 760

Warning 2 :
Warning: Cannot modify header information – headers already sent by (output started at /home/canariwa/public_html/Woo/wp-content/plugins/woocommerce-currency-switcher/classes/woocs_after_33.php:760) in /home/canariwa/public_html/Woo/wp-admin/includes/misc.php on line 1126

Also am unable to upload the flag images.
Theme am using : Woodmart

Please fix this as soon as possible.