maybe he's seen your message & already changed it, but *both* pages show `charset=utf-8' for me (Web Developer | Information under FF3.6.8).
I'm uncertain what the precise problem is. The first post *appears* to be a problem with text-on-page, yet *both* pages are fine, as far as I can tell. It seems, therefore, that the issue comes down to the URL itself: zdig1 wants non-ASCII characters within the URL, which has worked with one page (link provided), but not with the other (link also provided).
Using UTF8 in URLs is outside of my direct, personal experience (though I do not think that it will work), but I have an obvious question to ask: does this problem only appear when the non-ASCII part of the URL is a sub-directory name? I ask the question because that is the obvious difference between the two URLs.
Another observation: the working URL is a r-to-l language embedded within a l-to-r language (that is how it appears within my browser when I scroll through it; quite wonderful).
This next bit may offer a work-around whilst you find the actual problem: the `Response headers' page in Web Developer
show me the following Titles (I've changed the base-url for `<Base URL>':
Response Headers - <Base URL>/video/tags/%D8%A5%D9%8A%D9%85%D8%A7%D9%86-%D8%A7%D9%84%D8%B7%D9%88%D8%AE%D9%8A/
...whereas the non-working page shows the following:
Response Headers - <Base URL>/video/-d9-85-d8-b3-d9-84-d8-b3-d9-84-d8-b1-d8-a3-d9-81-d8-aa-d8-a7-d9-84-d9-87-d8-ac-d8-a7-d9-86/14-video_178296502.html
(you will understand from this that Web Developer
has converted the non-ascii-part to URL-encoded ascii)
I am unsure whether UTF8 URLs are currently supported. I know that plans are laid/already implemented/whatever, but would not be in the least surprised to find that they are poorly supported. The obvious workaround is to convert all your URLs using `htmlentities(urlencode($url-part))'
(be careful not to encode the directory separators). The browser will then auto-convert that URL-encoded string back into a readable string within the address bar.
You will need to carefully research the UTF8-support for urlencode(). I believe it to be good in PHP6, but you are using PHP5.2, and it is not so good.
One final thought: is the default language on your server UTF8?