Several errors since the update

I have a few troubles on drupal hotel booking management system.
First of all since i install the theme i recive update warnings about the rooms module and any time when i did some other parts of the syste m has been broken down (even i gave 0 for the children availibilty there is a message
Notice: Undefined index: children in book_units_per_type_form_submit() (line 1850 of /home/sultan/public_html/yeni/sites/all/modules/rooms/modules/rooms_booking_manager/rooms_booking_manager.module).).
The other huge problem is about the Bulk Availibility Management; i can see the list of the rooms however there is no calendar which supposed to be releated with the thrid problem which is about the fullcalendar missing error. Whatever i did to be able to install that plugin it never worked. First message was when i get to the status report section, it was written that fullcalendar is missing please install that and there was a link for it that i can find both 1.64 and 2.0 (beta) version. I download both of them and follow the instructions step by step and still no solution even it does not show me that error on the top of the list anymore when i scroll down the report it still says:

FullCalendar plugin At least 1.4.10
You need to download the FullCalendar plugin and extract the entire contents of the archive into the sites/all/libraries folder of your server.
Because i cant fix this isues i cannot move forward. I can upload the old database before the updates however that is not a solution because the old version did not allow me to choose "Show availability on a per-type basis." instead of "Show availability of individual units.". Show availability of individual units was the only and sellected option which causes tens of rooms listed below.