By writing the post above something has passed on my mind... and it is working now.
Windows64 uses two registers file - for 32 and 64. Each kind of app access its related data. So, regedit.exe apparently is managing only the 64bits register (there is a way to see and manage both by using the registry redirector and registry reflection - details on msdn).
So, all we have to do is download and install the appropriated version for our hardware architecture.
I was trying to be able to work with the 32bits (too) in order to get better performance comparison with the informations from those that doesn't have a 64bits machine.
(64bits + mult-threading rocks! 
)
Windows64 uses two registers file - for 32 and 64. Each kind of app access its related data. So, regedit.exe apparently is managing only the 64bits register (there is a way to see and manage both by using the registry redirector and registry reflection - details on msdn).
So, all we have to do is download and install the appropriated version for our hardware architecture.
I was trying to be able to work with the 32bits (too) in order to get better performance comparison with the informations from those that doesn't have a 64bits machine.
(64bits + mult-threading rocks! )