Internal server error, but why?

I have the KISGB php script installed in my website. It is not working at this time and I know that no one is busting the walls down to access my web site. Nevertheless, I keep getting this message (and many more like it) in the log file:
[Sun Nov 18 03:45:31 2012] [error] [client 66.249.76.78] PHP Parse error: syntax error, unexpected end of file in /home/rwarner/4warner/kisgb/index.php on line 964

The error is in response to this GET:

66.249.76.78 - - [18/Nov/2012:03:45:31 -0700] "GET /kisgb/index.php?action=view&tmp_theme=default.thm.php&tm p_lang=estonian.lang.php HTTP/1.1" 500 - "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"

Now, I understand, sort of, that a GET is a request from a spider to DOWNLOAD the module, but it apparently is trying to execute it (yes, there is an unexpected end of file).

I am getting hundreds of these requests daily (from Google and Baidu, apparently) wanting this information.

Why is Apache attempting to run the code in response to a simple (as I understand it) GET?
Is there anyway I can block these request (at least until I get the code fixed)?

Any information is gratefully accepted.

Thanks,

Bob