by Bernard J.
Thank you Dan for your reply.
The thing is that we have two moodle sites, the newset version and older 1.9 version. It is that way because we are slowly - slowly adapting and migrating to a new version of moodle, so thats why we are still using old one (until we migrate completely, which should be soon).
I am going to look for a newer version of that module for that moodle version, but I have a feeling that it is not a solution because the problem exists only on one course, with rest of them module works perfect.