smarty plug in error, unknown tag - 'html_options'

*Hi All* *I am getting the following error* *Fatal error*: Smarty error: [in myaccount.tpl line 22]: [plugin] unknown tag - 'html_options' (core.load_plugins.php, line 118) in */blah blah/Smarty.class.php* on line *1097* ** *Let me fill you in. * *I have three sites on the same server. Smarty is installed on one of the sites (the main site) with the PHP and the templates. I have written some php on the other sites that includes the scripts from the main site. This means i only need to update the code on one of the sites to make changes to all of the sites. * *Everything works great except smarty plugins through an error (see above).* *Do you have any suggestions on what this could be?* *Thanks in advance* *Scott*