I've re-installed from scratch a handful of times now, and deleted my map cache more times than I can remember (literally true, but I tend to lose count of big numbers, e.g. above about five, anyway...) but I still do not get the new naval map. So, naturally, I wondered why.
Scrutinising the files I got from GamersGate, the file provinces.bmp in "/mod/Dies_irae_Gotterdammerung/map" still shows the old map shapes. Could I please ask you to double check with the distributor (on Monday, obviously) that they have the correct files?
For what it's worth, my checksum is also AJFG (irrespective of whether I keep the HOI3 classic loading screens, or replace them with the DI:G screens).