PHP ping and exec() hangs apache

Hi, I stuck with strange error. I have following code: <?

    echo 'BEFORE';
    echo exec("ping -c1 -w1 1.1.25.38");
    echo 'AFTER';

?> Address doesn't exist. When execute script from command line everything works fine. But when I go to the file by Firefox it hangs out and apache need to be restart. This is a Virtual Server with PHP Version 5.2.6-pl222-gentoo. When address exists it works fine. Only problem is when it doesn't respond and apache hangs. I copy file to apache at my local apache and everything works fine. My apache is with Version 5.3.0alpha3-dev at windows XP. At old server with php4 everything works fine. I suspect that something wrong is with apache configuration but I don't know it for sure and couldn't find it. Thank you, Kamil Walas