XML-RPC Error (26045186)

After upgrading to the last version available new users cannot register at my site
I have upgraded moodle and the Joomla and the system check is OK
But when a user try to register at my site the following error appear

XML-RPC Error (26045186): E' stato rilevato un errore di programmazione, deve essere sistemato da un programmatore: moodle_database::get_in_or_equal() does not accept empty arrays | ERRORCODE: codingerror

Joomdle on Joomla is 1.1.0
Joomdle on Moodle is 1.1.0 (2008080282)

Joomdle plugins on Joomla

I would like to inform that only new user registration is not working. Old user can access the system because SSO is working fine.
It is also possible to define users in moodle and then importing it in Joomla.

I tried to go back to 1.0.8 to solve the problem but I've got some problems.
I installed the old version in Joomla and the system check shows different versions of Joomdle
So I tried to go back in moodle renaming the Joomdle directory in joomlde110 and copying the old version (108) and joomdle
I tried to install it but it failed. So I was forced to cancel the installation attempt and to rename joomdle110 to joomdle and reinstall the new version in Joomla.

I need a way to fix the problem.

I tried to install the 1.0.8 version in moodle and the system refused to do it showing "cannot downgrade" message.
I also set Joomdle in Joomla to not automatically create users in moodle but the the error persist.
I really don't know how to find a temporary fix.

In case anyone finds this problem: it is caused by an incompatibilty with Joomdle User Check plugin.
We will release a new Joomdle version this week, as we needed to update the package to meet new Joomla Extension Directory guidelines. A fix for this problem will also be included.

Thank you very much for your support
Claudio

You are welcome, thanks for your feedback.