Problem solved. After reading on the mailing list I found a item about an other problem with uclibc. Used from the BSD patches the part about sscanf() now it is working. (http://svnweb.freebsd.org/ports/head/multimedia/vdr/files/patch-vdr-1.7.28_F...)

And an other cheap HD platform for VDR is here. (Motorola VIP19xx sold over here in Holland for 5 - 25 euro.) No frontend module yet but the VDR backend is running.

Martin