Admin area errors - Warning: session_start(): The session id is too long or cont...

Hi,

A client of mine has been updating there website and they seem to have broken it. i cant seem to figure out the problem so i was wondering if any of you have come across this before. The errors are as seen below. They appear on the login page, i can still login but then i can only see the errors and cant see any of the actual admin area.

Warning: session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home3/ltjfansi/public_html/fireplace/perch/core/lib/PerchSession.class.php on line 9

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /home3/ltjfansi/public_html/fireplace/perch/core/lib/PerchSession.class.php:9) in /home3/ltjfansi/public_html/fireplace/perch/core/lib/PerchSession.class.php on line 9

Warning: Cannot modify header information - headers already sent by (output started at /home3/ltjfansi/public_html/fireplace/perch/core/lib/PerchSession.class.php:9) in /home3/ltjfansi/public_html/fireplace/perch/core/inc/auth.php on line 47

Warning: Cannot modify header information - headers already sent by (output started at /home3/ltjfansi/public_html/fireplace/perch/core/lib/PerchSession.class.php:9) in /home3/ltjfansi/public_html/fireplace/perch/core/inc/top.php on line 13

Warning: Cannot modify header information - headers already sent by (output started at /home3/ltjfansi/public_html/fireplace/perch/core/lib/PerchSession.class.php:9) in /home3/ltjfansi/public_html/fireplace/perch/core/inc/top.php on line 14

Warning: Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' 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 () in Unknown on line 0