Finally, I solved this question :-)
If you have the same problem (install openid plugin darcs version and not appears in the form login), changes at line 40:
$controller->register_hook('HTML_LOGINFORM_INJECTION',
for
$controller->register_hook('HTML_LOGINFORM_OUTPUT',
and it's runs ok! Another question is about the infinite loop "
Maximum of 5 delegations reached. Aborted"...
Xavier