free Argentina garmin maps

Hi,
I have a problem to convert a garmin map.
I've downloaded a free garmin map Argentina, chile from this site :

After this I use mapsource to convert it, and I have a file gmapsupp.img ( I try different size)

But when I try to use GPSMapedit I have an error :
Loading data from file 'C:\Carte Argentine pour Orux\gmapsupp.img'...
* Block size: 2048
* Updated: 2010/10
WARNING: Unexpected format of input data. No data offset field. This file may be failed to read.
* Defined: 00000918.MD2
* Defined: 00000918.MDR
* Defined: 00000918.SRT
WARNING: The map 54253066 is in NT format which is not supported by GPSMapEdit.
ERROR: Loading has terminated.
2 warning(s).
Load time is 0.01 s.
I don't know how to manage this, if somebody can help.
Thank you in advance.
Christian

I have same problem .but .img file another file.I dont understand this error/