BlogsMU Theme signup form - Blog URL suffix text incorrect for subdomain install

I couldn't find this issue in the forums, so thought I'd ask here.

Do you support the BlogsMU theme directly in these forums, or should I be trying to hunt down the theme owner?

The problem I'm having is with the signup form at the URL /register

Under Blog Details when the user checks the box "Yes, I'd like to create a new blog" there is an input box under "Blog URL (required)". For a subdomain install, the suffix text is incorrect.

What I expect to see here is http://( )

What I see instead is http://( )

I tracked this down to
.<?php echo str_replace( 'http://', '', site_url() ) ?>

I was able to fix it with:
.<?php echo str_replace( 'http://', '', get_site_url(1) ) ?>
where the argument value "1" is the blog id of my root domain (i.e.

Is this a known bug?