One off my user is getting a warning message saying 'alternative organization found' while entering the opportunity. It is specific to this user.
The reason could be that the org determination is based on parameter user.
That particular user must be assigned to more than one org, may be because of that u get the message alternative Organization found.
One Clarification -- where the error comes, which user interface. Is it SAP GUI, Portal or Webclient.
Since in case of SAPGUI, if more than one Orgs get determined, a pop up comes, whereas no pop ups are supported for webclient.Its advisable that only one org gets determined.