OK, a couple of other things to check.
Are your PT2 databases Access or Postgres?
If postgres, what version? The cache in PAH does not work with postgres 8.3 databases.
There is an issue in some rare cases that 1.19.6 can't build the cache correctly.
In these cases, you can install 1.18 and build the cache then re-install 1.19.6 and use the built cache as long as you don't then try to rebuild it again.