Shared calendar and Polish chars

[alan_space]

I've just installed shared calendar plugin together with SQL backend.
Everything looks fine except possibility to use Polish chars  in event name and description.
When I use them, the event name or description is not saved.
The system report that event was created/updated succesfully.
The name is changed into ...  and the event is not shown in the calendar. When I use the chars in description then the complete text is cleared/not saved.

Does anyone know how to solve the problem ?