That is strange ...
It generally either "just works" or it doesn't; the fact that the behavior is inconsistent might be an indication that something is wrong on DreamHost's end.
Of course, what you are describing can also be the result of caching (within your browser, if you are using wp-cache, your ISP, etc.)
To be sure that this is not the case, "clear everything" (how you clear your cache file(s) depends uppon your browser - just use the browser's help facility), close your browser (all windows!) and try again. I have even resorted to a complete system shutdown (computer, router, modem, and all) on occasion to get a completely "fresh" glimpse of a page (though the ISP could still be caching).
Also, depending upon the contents of your .htaccess file (separate sections for WordPress, etc.) rebuilding permalinks within WordPress could have over-written your changes.
If you would like for me to look at your .htaccess file for you, just respond back here including the contents of the .htaccess file currently in place in the "toot" directory of your WordPress installation (the directory above wp-content, etc.) and the url of your site and I will take a look.