I was getting this error trying to load formerly stable namespaces.

Execution error at etaoin.impl.client$call/<clinit> (client.clj:82).
No reader function for tag ns

problematic file?
https://github.com/clj-commons/etaoin/blob/master/src/etaoin/impl/client.clj

Clojure+ 1.6
Etaoin 1.1.43

I tried Clojure-mcp to fix it:
It believed the #ns data reader from clojure+ was conflicting with Etaoin's XML parsing.
It attempted to remove conflicting ns data reader before loading Etaoin.

It also played around sequential Etaoin namespace loading after jack-in, and could get Etaoin working. But could not produce a stable working cold start.

For now I have removed clojure+ entirely from project and can confirm that latest Etaoin loads normally without it.