When I visit the pages on which slideshow is not rendered my firebug shows me this javascript error:

element has no properties
[Break on this error] element.style.display = 'none';

In prototype.js:
931: hide: function() {
932 for (var i = 0; i < arguments.length; i++) {
933 var element = $ID(arguments[i]);
934 element.style.display = 'none';
935 }
936 },