Debugging
From b2evolution manual
Enable Debuglog
To have a Debuglog with a load of information on the bottom of each page, set
$debug = 1;
in /conf/_advanced.php.
Blank pages
Blank pages or sudden script abotion often mean that there's a fatal error during the PHP script execution and the website/server is configured to not display them.
A cause for this might be a parse error or the exhaustion of the memory limit).
You can try to look into the server's error log or add the following code to /conf/_basic_config.php (/conf/_config.php before b2evo 1.8):
ini_set( 'error_reporting', E_ALL ); /* report all errors */ ini_set( 'display_errors', 'on' ); /* display them on the page */
Add this after the opening "<?php" tag at the beginning of the page.
Note that this won't help, if you have a parse error in the config file you're editing itself, because PHP cannot execute the statements that change the reporting..
phpinfo
Often additional information may be useful/required.
Therefor you can setup a simple file in your web root directory like so:
<?php phpinfo(); ?>
Save this as p.php and give the URL to that file to the developer that asks for it or mention it in your bug report.
E.g., you can search on the resulting page for "safe_mode" to see if your installation is setup like so.