Arabic no longer shows. Just blank screen.

Well, I had it working - and now I've done something bad.

I have English, and Chinese, and did have Arabic all working nicely.
I updated a few files to put in a new header banner - and in the process I've done something because arabic now no longer shows the index page.
If I go to my site: http://www.chalmers.com.cn/ynot/zenynot/
It displays fine in English. If I select Chinese it displays fine in Chinese, but now if I select Arabic - I get the dreaded 500 Internal Server Error. The website cannot display this page.

I can't even think what is causing this now or where to look. I'm a bit ragged around the edges I confess now after a day of coding - and if any guru has an idea where I start looking, I'll be very grateful.

It has to be something simple. I hope someone can help.
thanks

I should add. The default language is English, with a pretty normal template.

Can I ask, what is called when I click on the [Arabic] icon from the index.php page.
If someone can tell me what is called. I can probably track it down.

index.php -> select arabic -> call ... what (arabic.index? maybe) nope. anyway - obviously something from that point on is failing, because it loads Chinese fine. It used to load Arabic - and something I did stuffed it.

Nearly time for a red wine I think.

Used the error reporting code.
enable_error_logging.php but it shows up the error in a file that has no errors ....

PHP Parse error: syntax error, unexpected T_STRING in
zenynot/includes/languages/arabic/header.php on line 23

But this line is fine - so it's obviously somewhere else... hmmm

So it sounds like a corrupted file somewhere. I guess as I asked before, what are the file involved in loading this particular file. On of them must have an error?

Fixed. Uploaded the backup using a GOOD ftp client. Corrupted file obviously.

Bad case of panic there for a while.

SO when the instructions say "keep your work backed up, as you go" they really mean it.

1. Presented with blank screen
2. used the error_checking.php script
3. PHP Parse error: syntax error, unexpected T_STRING in ...
   *Note, this doesn't necessarily mean it's where the error report says it is.
4. throw hands in the air.
5. Try to remember what important changes you made before your error struck.
6. Grit your teeth and just upload the main directories one at a time. Chances are you corrupted a file.
7. Make sure you can overwrite existing files.
8. I started with /includes directory - -> uploaded it, and everything worked.

Now to the next problem.....
hope that helps someone sometime.