The following message indicates that a model appears to be unidentified.

The specified model is probably unidentified. In order to achieve identifiability, it will probably be necessary to impose xxxxx additional constraint(s).

The (probably) unidentified parameters are marked.

The method that Amos uses for determining that a model is unidentified, and for determining how many additional constraints are required to make the model identified, is fallible. However, it is usually right. See Appendix D.