Actually, that looks like it's referencing one of the Mobipocket Creator files, as indicated by that URL. The error message "Object doesn't support this action" fits with that, since line 94 in the referenced file (C:/Program%20Files/Mobipocket.com/Mobipocket%20Creator/rsrc/html/table_of_contents.html) is part of the Javascript function "update_toc()", and the error message is a typical Javascript execution error. That line reads:
Code:
weholder.external.set_toc_parameters(document.forms[0].toc_title.value, parameters);
(The text on that line starts on character 3 because it's indented by two characters.)
Perhaps someone with a better knowledge than me of Javascript and using it to manipulate document objects might be able to suggest what might actually be triggering this error?