When did you book it?
From a legal standpoint, if you booked before the insolvency (I think December 21st) you could rebook it by now so your booking is surely not affected by insolvency law repercussions.
However, the running business is not the loss for Lindner but the rental contracts are. So the insolvency administrator obviously chose to fulfill all Hotel customer contracts, as we heard of no not fulfilled bookings.

I would say don't worry.