Hi geoffkennedy

,
If this problem is still not resolved:
With due respect to others who have tried to answer your problem, I think that your Wordpress blog is facing the
timestamp problem. There are many ways to check this:
1] First try using the Wordpress.com blog, i.e., start a blog using the wordpress.com and see if you can successfully post from there. This gives us a clue: If you can post from there using your laptop then the problem is definitely in your site's timestamp - solution is to ask your web-host: Forward this querry to your web-hosting service and ask them to look into the timestamp problems if any. This is because WordPress follows the timestamp. (eg, If you try to tamper with timestamp of a post - say put a future date, then the post will be published only when that particular time arrives in future, and not before that time... check this link: en.forums.wordpress.com/topic.php?id=1737&page,
[Incidentally, postdating can be quite interesting, you can automate your "Happy New Year 2008" post to appear exactly at 0:00 hours on January 1, 2008

without being online at that particular moment! The link explains all.]
Same could be the case for pre-dating the post... not very sure here because this is a special case... cannot do that trial to see what happens!
2] Ok, now as we know that current timestamp is important to get your post published successfully and obviously it is not working in your case, because you are mentioning "1999-11-30 12:00:00 am" in your querry. Now, also try saving any text or doc (using WordPad, NotePad, MS Word, etc) and see the time in the Windows Explorer of that file. If that shows the same "1999-11-30 12:00:00 am" then it is a problem of your laptop battery or some other internal malfunction. If it shows the current time, then obviously the problem lies in your WordPress installation /Website Hosting hosting / etc. If every other thing on your uploaded
website hosting / blog is fine datewise, then the WordPress installation is problem.
So, please try the above and then only try to change the mod_security settings.
3] To know more about mod_security (it is very critical and important, so know about it before upsetting it), check this link:
modsecurity.org/documentation/modsecurity-apache/1.9.3/html-multipage/
Hope you resolve the problem soon. Please give feedback here, and then invite us all to read your post!