What did I do wrong?

This appeared in my email box:

[3:06] Mobius Ryba: Bannana phones = bad
[3:06] Mobius Ryba: rez them outside of the MUVEnation sim and you would have likely been banned

I have no idea what I did. I still don't. Nitely, the owner of the tree where I added the banana phone was fine with it and just asked me to remove it:

[2:51] Tempest Nitely: Nellie could you do me a big favour and return to the surrealist tree on muvenation and delete the two banana phones you rezzed there. I can not return them to you because of the permissions set on the land and they are sure to drive everyone with a platform nearby completely crazy if they are not removed.

She encouraged me to keep experimenting as that was the purpose of Muvenation. However, the email I got from Mobius Ryba was very discouraging. The email is very unpleasant because it shows that I did something wrong, but what was it? What is a banana phone and where in the world did I get it?