Segmentation fault

Hi,

I’m getting segmentation fault when trying to access /wp-admin. I managed to get around it by commenting out the following code in the wp-admin/admin.php

if ( current_user_can( 'manage_options' ) )
        @ini_set( 'memory_limit', apply_filters( 'admin_memory_limit', '256M' ) );

This started to happen after server upgrade from debian 5.0 to 6 (php 5.2 to php 5.3).

Any ideas how to figure out why this is happening?