Tom Tom Navigator 5 - Palm e2 freezes on re-routing

I wonder if anyone else is experiencing similar problems - using a Tungsten E2 with the new 5.2 version of TT Nav 5, the PDA regularly 'hangs' needing reset when deviating from calculated itinerary - when it should be re-calculating a new itinerary.

The TT Nav 5 'version information page', i.e. after loading the TT application, gives between 0.6 and 0.9 mb of 'free RAM' (is that: 'dynamic RAM' - terms do not mean much to me)?! Even though there is plenty of 'actual RAM' when I check, more than 24 MB of it, have few additional apps loaded.

The map I have on the SD card is the large Germany-Suisse-Austria- Chech Rep. - Poland map, something like 420 MB.

Any ideas of what could be done to improve this?