Custom Sidebar Pro Upgrade Error

When I upgraded from Custom Sidebars Pro 2.0.7 to version I got 2 .php errors that were visible on both the front end and all admin screens. For now I have reverted to version 2.0.7 and the errors no longer appear. Here are the errors:

Warning: session_start() [function.session-start]: open(/home/content/42/3784742/tmp/sess_up9kri6mbkj2qp39099bo9mho6, O_RDWR) failed: No such file or directory (2) in/home/content/42/3784742/html/wp-content/plugins/custom-sidebars/inc/external/wpmu-lib/functions-wpmulib.php on line 73

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/content/42/3784742/html/wp-content/plugins/custom-sidebars/inc/external/wpmu-lib/functions-wpmulib.php:73) in /home/content/42/3784742/html/wp-content/plugins/custom-sidebars/inc/external/wpmu-lib/functions-wpmulib.php on line 73