Thanks for the replies! I discovered why reloading clipbd.e was causing trouble--I'd somehow deleted an important line from list-clipboards. PEBKAC!
But that doesn't solve the real issue of list-clipboards not behaving correctly.
Lee: I'm using VS 12.0.3, on Win XP SP2, in Vim emulation mode (I wonder if this matters? It's a highly consistent problem if I just copy three lines onto the clipboard, and try to paste whatever text is copied on to the middle of the list of clipboards, it usually pastes one of the other lines). I usually use the "dd" command to copy multiple pieces of text onto the clipboard. I haven't noticed any indications of corruption in the actual content of the list-clipboards dialog--nothing along the lines described by hs2.
I have not found reset-clipboards to be terribly helpful--at any event, it quickly becomes corrupt after copying more than three lines to the clipboard.
Is there any easy way to view the state of the clipboard ring besides list-clipboards?