I think that SYS0002 message is probably coming from lpadmin.exe, although without the full context (i.e. log) I can't be sure.
However, lpadmin.exe from CUPS 2.1.0 has no dependency on CUPS.DLL. In fact, nothing in CUPS 2.1.0 should have a dependency on CUPS.DLL. So I can only guess you might have an old version of the executable lying around somewhere that is getting called by mistake.