Which are the first lines in rainlendar2.ini?
If this file has something wrong, moving it will do nothing. (this is just for portable installation)
The rainlendar2.ini file store data as:
and your popup looks like is trying to say that an equal is missing in the second line.
If it was the case of a missing file, then is more likely to found "file not found" in the log.
About the "Invalid recurrence in component ..." could be a bad info or an unsupported event/task. Could you bring more details?