<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
# Skips the following S rules is they do not apply
RewriteRule ^.*$ - [S=1]
RewriteRule ^page([0-9]+).htm$ /okelly/okelly01.php?ArticleID=$1 [QSA,L]
</IfModule>
Put this is your root folder and try it. Remember also that when the URL is rewritten all relative paths within your output HTML with get thrown off, so make sure you use full URLs and paths to images, scripts and stylesheets or your output might look wonky.