Using WPTouch 1.7.5
I have a blog that's at myserver.com/blog. If I scroll down on a post's page on my iPhone using WPTouch, I see "You must login or register to comment". Both those links go to myserver.com/wp-<login/register>.php. No /blog, so the links are broken. I don't see a setting somewhere to fix this.
Login/logout using the link at the top of the page that makes the dropdown entry boxes appear does work.