http://bugs.winehq.org/show_bug.cgi?id=12107
--- Comment #5 from Dan Kegel dank@kegel.com 2008-03-19 13:24:04 --- WTF? On my work machine, those registry keys were created just fine on the first run. On the second run, the installer aborted with "CheckMediaSource returned 1603" (though find . -type f | xargs md5sum didn't find any unreadable files). Third run was fine again.
So perhaps the installer is a bit flaky? I'll run it a few more times on my compaq r3000 laptop (the one that had the original problem).