error changing account owner

error changing account owner

Hi,
After I select the new owner, and click the "ok", a error message appears, saying it´s not possible to the action that I required.
 
But all the account data disappear.
After that I go to the other user account (the new owner of the account), and some data is there, but only the task. nothing else.
 
Can anyone help me?
Thanks
eluis