Error on whmcs integration

I'm getting the following errors, any idea on what the problem is?

Warning: file_get_contents(/home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/cache/d3249ea8d75c32921a41f114c77e6589.txt): failed to open stream: No such file or directory in /home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php on line 376

Warning: file_get_contents(/home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/cache/d3249ea8d75c32921a41f114c77e6589.txt): failed to open stream: No such file or directory in /home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php on line 376

Warning: file_get_contents(/home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/cache/d3249ea8d75c32921a41f114c77e6589.txt): failed to open stream: No such file or directory in /home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php on line 376

Warning: file_get_contents(/home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/cache/d3249ea8d75c32921a41f114c77e6589.txt): failed to open stream: No such file or directory in /home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php on line 376

Warning: Cannot modify header information - headers already sent by (output started at /home/websitebuddy/my/wp-content/plugins/whmcs-wordpress-integration/includes/class-whmcs-wordpress-integration.php:376) in /home/websitebuddy/my/wp-includes/pluggable.php on line 1174