ios 6 mobile config

I tried to use iPhone Configuration Utility (3.5.0.289) to create a mobileconfig file for my now iPhone5 just now but it seem can't be work.

Please see the details as below:

Windows OS - Windows 7.

iPhone Configuration Utility 3.5.0.289

iPhone5 - IOS 6 (10A405)

When everything is fine, I send the config file to my email address and then use iPhone5 to receive it via "Mail".

When I click the file, it show error as below:

Invalid Profile

Profile could not be decrypted

What's is the problem?

Please advise, thanks.