[PHP] Question about session

[Bagus Nugroho]

I have session code which written WindowsXP and It wotk properly as expected, 
but when I'm used in Windows 2K, it got error as;
Notice: Undefined index: loginMessage in C:\CentralData\forms\mainForm.php on 
line 65
I'am used Apache 2.0 and PHP 5.0.4.
Is  php.ini setting on W2K different with XP

Thxs in advance
bgs
<!--
.style1 {font-weight: bold}
.style2 {
        font-size: 24px;
        font-weight: bold;
}
.style8 {color: #0066CC; font-weight: bold; font-size: 18px; }
-->