To fix this one need to add this code:
if ( $sl_options['show_avatar'] )
{
if( function_exists('bp_core_fetch_avatar') )
{
echo bp_core_fetch_avatar( array( 'item_id' => $current_user->ID, 'type' => 'full' ) );
}
else
{
echo get_avatar( $current_user->ID, $sl_options['avatar_size'] );
}
}