What does this supposed to mean Unfortunately your phone is not fully supported by Nokia PC Suite.?
 

I am running version 7.1.40.6 of Nokia PC Suite on Windows XP which was made for N900. After installation and connecting the device I see the message at the bottom:

I am planning to download the maps on to device. Device N900 is connected to PC via USB using Nokia PC Suite. Maemo 5 Version 3.2010.02-8.002 is on N900.

What seem to be the problem?

Re: What does this supposed to mean Unfortunately your phone is not fully supported by Nokia PC Suite.?
 

Did you check out this posting?

Re: What does this supposed to mean Unfortunately your phone is not fully supported by Nokia PC Suite.?
 

How when I try to connect via Mass Storage mode, I get: I am not sure what hell wrong with this thing.

Re: What does this supposed to mean Unfortunately your phone is not fully supported by Nokia PC Suite.?
 

That's normal - PC Suite won't work in mass storage mode, only in the (aptly named) PC Suite mode. That doesn't prevent the Nokia Map Loader from working though, as it just treats the N900 as an external disk.

Re: What does this supposed to mean Unfortunately your phone is not fully supported by Nokia PC Suite.?
 

It means what it says - N900 is not fully supported by PC Suite. And probably never will be as the current move is to put everything from PC Suite to Ovi Suite (tho Ovi Suite doesn't support N900 at all).

Maps Loader doesn't work in PC Suite mode on any Nokia device - you need to connect your device in Mass Storage mode to be able to use it with Maps Loader, and it works on N900 just like on any other N-Series device.