I tried PT4 with iPoker and it's running pretty good, but I have the same problem with iPoker than with PartyPoker:
-at first everything is ok and hud appear normally
-problems begin when I sit tables that I left previously in the same session: sometimes the hud appear, but 90% of time nothing happens, no hud on this tables, no PT4 icon on the window table (I can't select the table to run the hud)
It looks like PT4 don't arrive to record new hands of previously opened-closed tables.
To have a HUD again I have to seat out on all tables, stop import on PT4 (at this moment PT4 crash very often) then I launch PT4 again and click on "get hands while playing" so PT4 import all the hands missing (with a lot of duplicate), then I stop import to record hands in database.
I launch PT4 another time and HUD appears normally on all tables (sometimes I have the message to select table, but it works).