[Plugin: WordPress Mobile Pack] error message

error message in the bottom of /wp-admin/post-new.php

Warning: Cannot modify header information – headers already sent by (output started at /hermes/web03/b361/moo.minicomplainercom/wp-content/plugins/simplr-registration-form/simplr_reg_options.php:1) in /hermes/web03/b361/moo.minicomplainercom/wp-content/plugins/wordpress-mobile-pack/plugins/wpmp_switcher/wpmp_switcher.php on line 506