Don't know if this applies to UddeIM too, but did you see and try this FAQ ?

www.joomlapolis.com/content/view/3949/37/

on begin of comprofiler.php you have a few lines that you can add to uddeIM as well to display errors (blank page = silenced errors that are also in your servers' error log normally...)

[code:1]if($_CB_framework->getCfg( 'debug' )) {
ini_set('display_errors',true);
error_reporting(E_ALL);
}
[/code:1]

would translate for joomla 1.0/mambo into:

[code:1]global $mosConfig_debug;
if( $mosConfig_debug ) {
ini_set('display_errors',true);
error_reporting(E_ALL);
}
[/code:1]

add that at top of com_uddeim.php and turn site debug on or just:

[code:1] ini_set('display_errors',true);
error_reporting(E_ALL);
[/code:1]

at top of your main index.php file of your site and all silenced errors will be displaying....