large (200k) html file with nested tables does not load into MS Word

I'm using  standard content disposition headers (ie:"application/vnd.ms-word") to create the page, but the page (which loads fine in html) either does not load at all in word, or, it takes Much too long (minutes) to load.   I have tried:
- saving the file and loading from disc
- stripping out generate javascript
- removing headers and footers
- testing the resulting html for properly formed tables and such
- bypassing the fusebox stucture
- stripping out tabs
- stripping out hidden tags
- stripping out CRs
Does anyone have any experience in this?  I'm reusing existing code, so I'm stuck with the level of table nesting (yeah, yeah, I know, use stylesheets for presentation)