Nearly a month after the problem was first reported, we are still getting reports of the improperly loading post editor sessions from bloggers in Singapore.
This problem, apparently being related to your Internet service, can't be seen by Blogger, or by anybody but you (and your neighbours). If you don't report your problem, don't expect for it to go away. And possibly, you should be reporting the problem to your ISP too. And please, when reporting the problem at this end (either in Blogger Help Forum, or comments here), state explicitly whether you are in Singapore or the vicinity, and whether your ISP is SingNet.
If there is no tab pair for "Compose" / "Edit HTML", check to ensure that Compose mode is enabled for your account.
(Update 2009/09/05): It appears that this problem is still with us.