In our group (university), we have 4 ics calendars located on a shared network drive. The people who want can put them into their rainlendar (Version 2.0.2 (b32), WinXP pro SP2) as "local" calendars, with a drive letter mapped to the network drive.
We have seen strange behavior (I'm working on a better description ). E.g. I added an event this morning, and it showed up on everybody else's rainlendars (as it should). However when I look at the .ics file, this event is now the only event in that file.

On the other hand I could see other events (that were in the file before) in my calendar. It seems that my rainlendar (that wrote the new event to the file) must have somehow lost all the old events.

I'll try to reproduce this, and let you know more.

I don't recommend putting the ics file to a shared folder if there is a chance that multiple clients access it at the same time. The system hasn't been designed to work that way so it is possible that the ics file gets corrupted if it is accessed simultaneously.