DdeNameService: expansion of stub to trap unused instanceids at start of run.
DdeGetLastError: catch 'not initialized' situation and return correct response.
DdeFreeStringHandle: complete test for error set by previous call of
something and ignore it, also release handle table mutex on normal exit.
DdeQueryStringA, DdeQueryStringW, DdeCreateStringHandleW: Release
handle table mutex on normal exit.