trouble using {php}include(filename);{/php}

Elsewhere in the forum I saw where someone was told how to include a php file using this syntax: {php}include(filname);{/php}

On my site I have a navigation bar that is included on each *.shtml page using a SSI statement:
<!--#include virtual="../navbar2.htmlf" -->
and each *.php page using include():
<?php include("../../navbar2.htmlf"); ?>

Of course the point is to update only navbar2.htmlf when a change is needed.

In order to make G2 appear like every other page on my site, I tried to add it to public_html/gallery/themes/classic/templates/local/theme.tpl using this statement:
{php}include("/navbar2.htmlf");{/php}

But I get this error message:
Warning: main(/navbar2.htmlf) [function.main]: failed to open stream: No such file or directory in /home/hrsmsor/public_html/gallery/g2data/smarty/templates_c/%%3361524034/%%C7^C79^C790B080%%theme.tpl.php on line 50

Site is http://66.249.137.29 (domain name hrsms.org being transferred)

Thanks in advance !!!

Yes, the navbar2.htmlf is in the public_html folder.

I thought starting with a slash would make the path relative to public_html.
I know I've used it that way with success before, but perhaps not for SSI or PHP includes. I know for sure it is working for linking-in my css file. Is this not legal for a PHP include? I'm at work and this code is at home. I'll look this evening to see if I've used it that way in the past. Even if I have, maybe it doesn't work with the smarty code (which is 100% new to me starting with last evening).

I've never seen/used a path starting with /home/... I'll try that.

Thanks.