Why does Yap's MYDDAS (MySQL coupling API) fail to work?

Using Yap Prolog 6.2.0, and MySQL 5.1.41, and trying to use db_open .

http://www.dcc.fc.up.pt/~vsc/Yap/documentation.html#MYDDAS

Prolog source:

:- use_module(library(myddas)). 

:- trace, db_open(mysql, x, localhost/myschema, web, mypassword),
   write('got it'), nl.

A trace of the failure:

?- db_open(mysql,x,localhost/myschema,web,mypassword).
(1)    call:db_open(mysql,x,localhost/myschema,web,mypassword) ? 
(2)    call:myddas:db_open(mysql,x,localhost/myschema/0/_131406,web,mypassword) ? 
(3)    call:myddas_errors:'$error_checks'(db_open(mysql,x,localhost/myschema/0/_131406,web,mypassword)) ? 
(3)    exit:myddas_errors:'$error_checks'(db_open(mysql,x,localhost/myschema/0/_131406,web,mypassword)) ? 
(4)    call:myddas:c_db_my_connect(localhost,web,mypassword,m开发者_Go百科yschema,0,_131406,_131634) ? 
(4)    fail:myddas:c_db_my_connect(localhost,web,mypassword,myschema,0,_131406,_131634) ? 
(2)    fail:myddas:db_open(mysql,x,localhost/myschema/0/_131406,web,mypassword) ? 
(1)    fail:db_open(mysql,x,localhost/myschema,web,mypassword) ? 

---

Seems compiling Yap with --enable-myddas --enable-myddas-stats --enable-myddas-top-level is required.
Compiling it (as I had done previously, i think) with --enable-myddas --enable-myddas-top-level did not work.