On updated content triggered action conflict with CCK

I have a triggered action which works to replace one vocabulary term with another (in the same vocabulary). It works very well. However, I encounter a problem when I try to publish or unpublish content. When attempting to do so, I get several CCK error messages which read:

warning: Invalid argument supplied for foreach() in /home/zowdacom/public_html/modules/cck/content.module on line 1244.
warning: Invalid argument supplied for foreach() in /home/zowdacom/public_html/modules/cck/content.module on line 1284.
warning: Invalid argument supplied for foreach() in /home/zowdacom/public_html/modules/cck/content.module on line 1284.
warning: Invalid argument supplied for foreach() in /home/zowdacom/public_html/modules/cck/includes/content.token.inc on line 39.

My code is below. The error only occurs when this code block is triggered:

function remove_all_terms($node, $old_term_array){
foreach($old_term_array as $key){
$node = rules_action_taxonomy_term_remove_from_content($node, $key, $settings);}
return $node;
}
$vid = $taxonomy_vocab->vid;
$oldterms = taxonomy_node_get_terms_by_vocabulary($node, $vid);
$old_term_array = $oldterms;
$node = remove_all_terms($node, $old_term_array);
return array("node" => $node[node]);

A final symptom of this problem is that a new node is created at the same time that the error message occurs. The node is blank. It has no title, no content, it doesn't even have a type. The only thing it has is an author name "visitor".

This is a major problem for me, because I need this replacement functionality. If anyone could help shed some light on this, it would be appreciated.