[horde] rpc - ICS ... Server Error

[Martin Hochreiter]

Hi!

I dont get the ICS Calendar any more  - lightning does not load anything.
If I open the URL in Firefox the site stays blank ...

If I open the URL via wget I get "Internal Server Error 500"

Nothing in Apache or horde log ... and the whole thing was working until 
yesterday.

Where can I start here?

Regards
Martin

(I am using always the latest horde&imp&kronolith via pear)