Can't delete entries from "Programs to Remove" list

I have two entries in my Programs to Remove list that don't show up in the standard Windows uninstall utility. The two entries pertain to a program that is no longer installed on my computer. ccleaner won't uninstall them, which is fine, because I think they really are uninstalled. But what I would like to do is just remove/delete the entries from the Programs to Remove list. But when I click on Delete, I just get a "Cannot delete MSI installer" error message. I tried following the instructions I've seen elsewhere to dig down into

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall

and

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall

but that hasn't done the trick (nothing was there for these entries). Is there anything else I can do to get rid of these entries?

I'm using CCleaner (free) v5.42.6495 (64-bit) on Win7 Ultimate 64-bit SP1.