This is reproducible on the latest version (as of 11/21/2011) of the cutesoft demo.
Test Case #1:
1) Go to HTML view and select and delete all text,
2) return to Normal view,
3) you will be unable to insert file links.
Test Case #2:
1) Clear the page in Normal view
2) Insert file link (OK)
3) Without taking any other action, try immediately inserting another file link
Problem will occur (FAILS)
IE + FF experience, so it's probably on all browsers.