Products-comparison 500 error

[artuha]

Hello!

Version 1.6.0.9. I've an error 500 in products-comparison page. If I enable to show php errors, there're:

Notice: Trying to get property of non-object in /var/www/svddru/data/www/svdd.ru/cache/smarty/compile/ed/74/9d/ed749d

Notice: Undefined index: ajax_allowed in /var/www/svddru/data/www/svdd.ru/cache/smarty/compile/ed/74/9d/ed749d2af11acf978d4f6deb923e55d40a3b9d12.file.blockcart.tpl.php on line 86

On 86 line:

<?php if ($_smarty_tpl->tpl_vars['ajax_allowed']->value&&isset($_smarty_tpl->tpl_vars['blockcart_top']->value)&&!$_smarty_tpl->tpl_vars['blockcart_top']->value) {?>
				<span class="block_cart_expand<?php if (!isset($_smarty_tpl->tpl_vars['colapseExpandStatus']->value)||(isset($_smarty_tpl->tpl_vars['colapseExpandStatus']->value)&&$_smarty_tpl->tpl_vars['colapseExpandStatus']->value=='expanded')) {?> unvisible<?php }?>">&nbsp;</span>
				<span class="block_cart_collapse<?php if (isset($_smarty_tpl->tpl_vars['colapseExpandStatus']->value)&&$_smarty_tpl->tpl_vars['colapseExpandStatus']->value=='collapsed') {?> unvisible<?php }?>">&nbsp;</span>
			<?php }?>

And I actually can't find the reason. How to investigate this issue?

 

Thanks for any suggestions.