[Plugin: Link to Post] 404 Header from MCE button

So I’m getting a 404 error when I click the link to post button. It does actually process the file, but the result is a 404 thrown from core stuff.
Stack trace to where the 404 is thrown:

#0 WP->handle_404() called at [C:\-\public_html\wp-includes\classes.php:511]
#1 WP->main() called at [C:\-\public_html\wp-includes\functions.php:1504]
#2 wp() called at [C:\-\public_html\wp-blog-header.php:16]
#3 require_once(C:\-\public_html\wp-blog-header.php) called at [C:\-\public_html\wp-content\plugins\link-to-post\tinymce\linktopost.php:2]

WP 3.0.1, PHP 5.3.3, IIS 7.0