Ok - I see it now when I actually use the tool.
curl_init is only the initialization function for the curl extension, so you also need to replace any curl_setopt, curl_exec, and curl_close function calls. If I am reading the docs correctly, the purpose of these functions is to fetch a remote HTML page and print it to the page being served to the browser. If that is how they are being used in your tools, you should take a look at
PHP's filesystem functions. As long as allow_url_fopen is set to "1", which is the default, they can be used to access remote documents over http or ftp. Note that this setting can only be specified in the systemwide php.ini, so it is up to the sysadmin whether or not it is set.
Assuming it is, you could probably replace all the curl functions with a
readfile call. This function prints a file to the document being served, and if allow_url_fopen is set to "1", it can do the same for remote files.
[Edit] If you are using seo tools from
seobook, then you might be able to simply replace the $google->curl_string($url_page,$user_agent); calls with $google->getUrl($url_page); calls, though you'll first have to edit the google class to add the getUrl function from
their UltimateSEO class.