That is strange, I use .htaccess Redirects all the time and they work fine. You just need to make sure the source is referenced from the document root, while the destination needs to be a full URL.
Just looking at the example I gave previously, I seem to have forgot a leading slash. I am not sure if the slash is required, but it may be.
[color=#0000CC]Redirect 301 /tv.htm http://www.evevancouver.ca/tv.php[/color]
As I said in my previous reply; If your sole aim in changing the files from .htm to .php is to allow you to use PHP code in your pages, I would advise that you simply enable PHP parsing in .htm files, rather than having lots of redirects.
Save [color=#CC0000]$50[/color] on DreamHost plans using [color=#CC0000]PRICESLASH[/color] promo code (Click for DreamHost promo code details)