Why does the preferences-app crash when I try to add a CalDAV-account?

Hey all,

I recently set up a calendarserver on my debian-machine. After that, I set up my account in iCal on my MacBook. Everything works, so my server does.

Now, if I try to add a CalDAV-account on my iPhone (preferences-app -> Mail, Contacts, Calendar -> Add account -> Other -> Add CalDAV-Account) the preferences-app crashes and nothing was added.

Any suggestions how to solve this issue?

My iPhone 3GS runs with iOS version 4.3.3 (8J2).