Went to bluehost today with the same code and the plugin (I know its my plugin b/c when I delete it all is well) breaks wp-admin.. .the website itself works fine, but when I try to go to wpadmin it is just a blank page…
Just a single line line break added some how during transfer of php files can create problems. Usually a line break added during FTP transfer gives some specific HTTP error code. For white page, check the php error log files to get the line number and specific php file.
On Bluehost your php errors are reported to a file called error_log, in the folder that caused the error. Also did you set your plugin to report it’s errors using wp_debug? If so you can just change your wp-config.php to have true for wp_debug, which will make your errors print on the webpage instead of just showing a white screen.