Can somebody please help me with Nokia Messaging?

I got an SMS from NM for the download link.
I clicked on the link, then it takes me to:

Choose a platform from the list below that best matches your device type
I selected Symbian Series 60 5.0 ( Its not showing me Maemo platform option)

Then when i download it to the device. I am not able to open it.

When I the downloaded file, it says:
Select an application form the list to open file 'Nokia'

How to go ahead from here?