Having had a nightmare trying to get clean urls with textpattern up and running on my shared hosting @ 1&1 i eventually stumbled upon a solution after much time scouring the txp fora

If anyone out there is trying to get clean urls working on textpattern with 1&1 (and lets face it, who wants a messy url!) the solution is to update the out of the box txp htaccess file so that RewriteBase is defined as follows:

DirectoryIndex index.php index.html
Options +FollowSymLinks
RewriteBase /
<IfModule mod_rewrite.c>
 RewriteEngine On
 RewriteCond %{REQUEST_FILENAME} -f [OR]
 RewriteCond %{REQUEST_FILENAME} -d
 RewriteRule ^(.+) - [PT,L]
 RewriteRule ^(.*) index.php
</IfModule>
#php_value register_globals 0@

Hope that helps someone as had me fuddled for a wee while….