why ob_start("ob_gzhandler") crash my IE

[Anon]

when I try to use ob_start("ob_gzhandler") in PHP (v4.0.5)
sometimes, I'll get the error message from IE 5.x (memory access error),
but sometimes not (in the same page)

does anyone know how to fix it ?

ps: I use zlib-1.1.3

thanks for your help!