这个问题早在2005年就有人提出，然而到现在IE6都没有解决。看来微软确实是彻底放弃IE6了：

drusunlimited said on Jun 16, 2005 at 7:18 AM:
I have found a bug in Internet Explorer that affect flash: when a query is done to a server an the server response in content enconding:gzip, the explorer don´t communicate with the flash activex.
I finally found a solution, changing the server settings in order of don´t use this content encoding mode. But the problem exists.
Good luck.

2007年7月，也有人遇到类似问题：

It seems there is an issue when Flash Player 9 running in Internet Explorer receives GZip-encoded content from the server. While IE has no problem with GZipped content on it’s own, it apparently fails to unpack and deliver the content to the Flash player.

这是IE6若干安全问题之后的又一败笔。请立即升级IE6到IE7（为什么要升级），以确保您能正确地观看网页，并且足够安全。