MS XML 6 / VBA - selecting ancestors?

I've been trying different approaches to get the ancestors of a node but am getting this error message:

2147467259 (80004005) Expected token 'eof' found ':' ancestor-->:<--:*

for: ?oRptNodes(1).SelectNodes("ancestor::*").length

Should I be able to use "ancestor" in Excel VBA with MSXML 6?

Thank you