To reproduce: use a German TimeZone

1. Create a recurring appointment with a yearly recurrence rule on the last Sunday of October.
2. Export to iCal. As a result, the TimeZone information is not correct. 

The exported RRULE BYSETPOS=5  defines the 5th Sunday. This is wrong. There may be a year with 5 Sundays in March/October but that is not true for every year. The correct encoding for ics files is BYSETPOS=-1. This indicates the last Sunday of a month. The other error is the DTSTART:16010101T030000 and DTSTART:00010101T020000. The German daylight rule is valid since 1996, not since 1601 or year 1. 
Note: German timezone defines the switch to daylight saving time as
- start on last Sunday in March at 03:00
- end on last Sunday in October at 02:00
This rule is valid since 1996.

Alert: Events created in RadScheduler for the last Sunday of a month are correct! The rule here is exported as expected and contains BYSETPOS=-1: