This is the configuration: Windows 7 Home Premium, XAMPP 1.7.3 (Apache 2.2.14 , PHP 5.3.1), Firefox 3.6

This is the PHP-code in a file named 'test.php' in htdocs:

<?php echo('04556-8978765'); ?>

On http://localhost/test.php I would expect to see the string 04556-8978765 in the browser. This is not what happens, though. The string appears for a short time and then it disappears altogether. Firebug shows an empty body-tag. However, when I look at page source, the string is there alright.

When I change the string in the echo-statement to e.g. 4556-8978765, everything is fine.

Internet Explorer 8 does not show this strange behavior.

I could not reproduce this with the same Apache/PHP/Firefox configuration on Windows XP.

'04556-8978765' is by no means unique. The couple '02065-96047' and '02065-9604' behave exactly the same.

Can anybody reproduce this and offer an explanation as to what is going on?

PS: If you can not see the string '04556-8978765' in the echo-statement above, look at this post with IE8.