I don't know exactly what that means, but from what I make up from wikipedia is that the userland is the environment where software is in and the kernel is "the OS".
Afaik both are x86_64. I just installed everything with apt-get so I don't think anything 64-bit is installed. As far as I can see (I don't have access to the host OS) both the OS host and the guest are x86_64 too.
How exactly can I check which userland is used and what do I have to do to correct it?