Customer reg error !!! help me !!!

I need your help. very urgent

I have a problem with my shop when a customer register, to complete launches a new page with this ....

Warning: Cannot modify header information - headers already sent by (output started at /home/as000509/public_html/catalog/language/spanish/account/create.php:1) in /home/as000509/public_html/system/engine/controller.php on line 23

and the client receives this email

mail_line_1 mail_line_2 http://demo.com/index.php?route=account/login mail_line_3 mail_line_4

I check the spaces... but all is good...

Please help me..

??

Check for spaces in the language files for that page.