After showing off my N95-3 GPS function with the maps of Indonesia and Taiwan pre-installed on my MicroSDHC 4GB to my relatives in Asia (one with a N95-1 and the other with E90), they asked for my help to set it up for them. As I recalled, the process was fairly simple. I remembered downloading Nokia Map Loader software and within half an hour, I was able to get all the regional maps I wanted.
When I attempted to install the maps onto the Nokia E90, it would not recognize the maps on the MicroSD card. I used the latest version of Nokia's map loader (v 1.3) and attempted the installation process over painstakingly slow DSL speed in Jakarta (50MB took 40minutes) three times, I finally remembered what went wrong: outdated handset firmware! Back when I first got my N95-3, I had immediately installed the latest firmware and then installed the maps...
So to save my fellow mobile experience readers from the same agony, if you want to install Nokia Maps, please remember to:
1. Get the latest Handset/Communication firmware
2. Get the latest Nokia Map Loader and follow the instructions on screen