If you are having problems using virtual include becuase of files being stored in different directories, a root-relative path will make things much easier:
virtual ("/root directory/directory/filename.htm/");
where root directory is the root directory of your site (ask your sys admin if you dont know what it is) Don't include the protocol or host name.
This will also allow you to move your files around your site without having to redirect your includes which is *very* helpfull