I installed the wp-pear-debug plugin and tried to activate it. It gave a PHP parse error.
On inspection, I found in Line 373 :
<? if($sField['def'] != self::WPD_GUEST_ROLE): ?>
It should have the php start tag and should be changed to :
<?php if($sField['def'] != self::WPD_GUEST_ROLE): ?>
Please integrate it to trunk code for the plugin.