Hey @moxious,
The reason your seeing this error is actually a little deeper than you might have noticed at first glance. The issue is not so much that we are using inheritance at the query class level, but rather that NPM manages dependancies on a per-module basis. In effect, what this means is that when you require the couchbase module into your application, and then we require couchbase into Ottoman.js, if the versions do not match, different modules are included. This means that the bucket you pass to ottoman has one idea of what N1qlQuery is, but the N1qlQuery that Ottoman.js is using to create queries is different (from its own version of the couchbase module).
Cheers, Brett