Session_start Error

Hello,
I keep getting the following errors on my DirectoryPress site. When I remove line 16, all the errors disappear. How can those errors be fixed? Is it safe to remove the line “session_start();” from functions.php?

Thanks.

Warning: session_start() [function.session-start]: open(/tmp/sess_067758c30061e3778176045aff6538d5, O_RDWR) failed: Permission denied (13) in /public_html/wp-content/themes/directorypress/functions.php on line 16

Warning: Unknown: open(/tmp/sess_067758c30061e3778176045aff6538d5, O_RDWR) failed: Permission denied (13) in Unknown on line 0

Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0