Do you have any custom installation paths going on? Like either the sims or the CA Amps or maybe even Sonar itself?
Sounds like the CA Amp chains just can't find TH2/3.
Also, and this one's for Craig, do I recall you releasing an update to some of the earlier amp chains you released? It was a long time ago but I seem to remember some issues being reported and you providing a fix. I could be thinking of something else though.
Maybe OP is running an older incarnation of the Amp Chains?
/spitballin'
//hasn't used the CA amps yet