Thank you, using the driver from the realtek website works.
The only problem was, that the makefile use the currently running kernelversion for the library directory (in my case a rescue system), that is different from the kernelversion in the normal system. I had to modifie this file:
src/Makefile
#OLD:
KVER := $(shell uname -r)
# TO NEW:
KVER :=2.6.18-028stab051
#its used for:
KDIR := /lib/modules/$(KVER)/build
KMISC := /lib/modules/$(KVER)/kernel/drivers/net/
(Maybe it can help someone other.)