Pages are displaying 404 Not Found

I have a recently installed blog (1.5.2).
Just setted permalinks this way “/%postname%.html” and updated my .htaccess.
Everything seems to be ok, except for the pages. When I create a new page it goes to the sidebar with no problems, but when I click on the page it throws a 404.
It doesen’t happen in localhost, but I have no permalinks there.
If the problem is not too difficult to solve I would really appreciate any help provided.
If anyone wants to take a look at the online site and help me to test it I will write the address. (I didn’t because it’s an spanish blog)

Thanks a lot.