Writing area goofed up with 2.6?

Hi. I maintain two blogs. One in English and the other in Japanese.

Both of them have problems with writing after update number 2.6! ??

(1) In both, the TinyMCE Advanced plugin settings are not being honored in my “Write Post” page in WP admin. I am seeing the default WP 2.6 write text box! What am I missing?

(2) More bafflingly, in the Japanese blog admin, my posts show up in the write page ONLY in the “Visual” tab, but they have HTML inside the text box from the original! When I click on “HTML” tab, nothing happens! And there are no menu bars on this text box at all — not TinyMCE, nor the default 2.6 write box!

Where can I look to correct these issues? I disabled the TinyMCE Advanced plugin but these issues still persist so I doubt it has anything to do with that plugin? At this stage, I don’t mind not using it, but I would like the Text box to work in a more predictable manner.

Thanks!