PHP 4.0.6/Win98/Sessions

Hi, I'll tell you about my setup first. I'm using PWS on Win98 and PHP 4.0.6 so I can test my website before I publish it. When I was using PHP 4.0.5 everything worked great. Then I upgraded to 4.0.6 the day it came out and all of a sudden sessions don't work anymore! I look in my sessions folder and all the information is in the file but for some reason PHP can't read it. So then I downgrade back to 4.0.5 and, changing nothing else, it all works again! Has this happened to anyone else? Is this a problem with my settings? I kept my old php.ini file when I upgraded to 4.0.6, should I have done that? Please help. Thanks, Paul Smith