A duplicate value for unique key member GeneralInfo.user_id found

I am getting this error:

System.Runtime.InteropServices.COMException (0xC1004042): A duplicate
value 
for unique key member GeneralInfo.user_id found while building indices for

profile UserObject. Check the underlying store for uniqueness of the 
property. at 
Microsoft.CommerceServer.Interop.Profiles.ProfileServiceClass.CreateProfile(Object

sValue, String bstrType) at 
Microsoft.CommerceServer.Runtime.Profiles.Profile..ctor(ProfileContext 
profileService, String keyValue, String profileType, Boolean
retrieveProfile)

I believe that duplicate GUID's are created when Anonymous accounts are 
created.

Please help me get rid of this.