Currency issues

started getting these errors OC Version is 1.5.3.1 no real major mods installed any help appreciated

2012-08-31 6:31:27 - PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxx/public_html/index.php:49) in /home/xxxxx/public_html/index.php on line 177
2012-08-31 6:31:27 - PHP Notice: Undefined index: HTTP_HOST in /home/xxxxxxx/public_html/system/library/currency.php on line 45
2012-08-31 6:31:27 - PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxxxxx/public_html/index.php:49) in /home/xxxxxxxx/public_html/system/library/currency.php on line 45
2012-08-31 18:55:49 - PHP Warning: session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cookie - headers already sent by (output started at /home/xxxxxxxx/public_html/index.php:49) in /home/xxxxxxxx/public_html/system/library/session.php on line 11
2012-08-31 18:55:49 - PHP Warning: session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cache limiter - headers already sent (output started at /home/xxxxxxxx/public_html/index.php:49) in /home/xxxxxxxxx/public_html/system/library/session.php on line 11
2012-08-31 18:55:49 - PHP Notice: Undefined index: HTTP_HOST in /home/xxxxxxxx/public_html/index.php on line 177
2012-08-31 18:55:49 - PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxxxxx/public_html/index.php:49) in /home/xxxxxxxx/public_html/index.php on line 177
2012-08-31 18:55:49 - PHP Notice: Undefined index: HTTP_HOST in /home/xxxxxxxxx/public_html/system/library/currency.php on line 45
2012-08-31 18:55:49 - PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxxxxx/public_html/index.php:49) in /home/xxxxxxxxx/public_html/system/library/currency.php on line 45


Regards

Eddie