Vtiger: I can't add a To Do event

If I got to calendar, click on To Do, then try to add an event, the form pops up, I fill it out, press save, but no Event gets added. In the SQL error log's I see an error like this:

2011-09-29 14:57:07 EDT ERROR:  null value in column "visibility" violates not-null constraint
2011-09-29 14:57:07 EDT STATEMENT:  insert into
vtiger_activity(activityid,subject,date_start,time_start,time_end,due_date,status,eventstatus,priority,sendnotification,activitytype,visibility,duration_hours,duration_minutes,location,recurringtype,notime) 
values('235','Testing','2011-09-29','19:50',NULL,'2011-09-29','Not Started',NULL,'High','0','Task',NULL,NULL,NULL,NULL,NULL,'0')

So, for some reason, it is trying to add a To-Do while inserting null values. My biggest problem is that I cannot locate the origin of the query. So, basically, the most important thing I am asking is what file takes the data that was input into the todosave form and turns it into a query.

I don't know if many people on here use Vtiger, but I couldn't figure this out so I went ahead and posted anyway. The official documentation is not very helpful in my opinion.

Thanks for everything, have a good day.

This might be an isolated case, but was any of the modules modified recently? In this case, I would assume that it would be the Calendar module. I've tested this on the demo website and on my vTiger installation and it works fine..

Perhaps you can download a fresh copy of vTiger and replace the modules/Calendar all its content.

By the way, another place to ask if you have any questions, is the vTiger forums.

http://forums.vtiger.com/index.php

Usually you can ask it in the Help - 5.2.1 section. Hope this helps!