Does anyone know why the following code doesn't work using kix4.22 final release?

$objUser = GetObject("LDAP://server/CN=User,OU=Group,DC=site,DC=com")
? @ERROR
;Clear any current entries
objUser.PutEx(1,"otherTelephone",0)

;Add the new entries
objUser.PutEx(3,"otherTelephone","111-111-1111")
? @SERROR
objUser.PutEx(3,"otherTelephone","222-222-2222")
? @SERROR
objUser.PutEx(3,"otherTelephone","333-333-3333")
? @SERROR
objUser.PutEx(3,"otherTelephone","444-444-4444")
? @SERROR
objUser.SetInfo


The error string I get at each line is
COM exception error "PutEx" (Active Directory - Unspecified error) [-2147352567/80020009]