Van Horn, there are no problems installing OpenFTS (the openacs package). The message you get is just a warning in the aolserver logs that says there is no FTS engine installed (not necessarily OpenFTS). Remember the search package supports multiple search engines through the use of service contracts (FTSEngineDriver).
Now, w.r.t the problem you get when you try to install OpenFTS (not the OpenACS package but the real thing) is due to the fact that the installation scripts are based on PostgreSQL 7.1. Postgresql 7.2 changed the place where include files are stored (serve side includes). Therefore, the error you get. As you understand it was difficult to foresee such a change last Summer when OpenFTS was first released. The new (upcoming) OpenFTS version is based and requires 7.2.
