Hi,
i have found it!
It is because of de PHP version.
externallib.php uses the abreviated sintax to declare arrays [] that doesn't work in PHP 5.3.3
I have changed those declarations and now it works!
Here are de diff between the original file and the modified one:
7697c7697
< $viewablefields = array();
---
> $viewablefields = [];
9402,9403c9402,9403
< $result['someoptions'] = array();
< $result['alloptions'] = array();
---
> $result['someoptions'] = [];
> $result['alloptions'] = [];
9535c9535
< $errors = $accessmanager->validate_preflight_check($provideddata, array(), $currentattemptid);
---
> $errors = $accessmanager->validate_preflight_check($provideddata, [], $currentattemptid);
9639c9639
< $errors = $accessmanager->validate_preflight_check($provideddata, array(), $params['attemptid']);
---
> $errors = $accessmanager->validate_preflight_check($provideddata, [], $params['attemptid']);
Thanks for your help!