Hi! Thanks for your help.
1.) Don't change kernel-location but create a link "linux" on linux-2.4.20-8, DVB-driver Make should autodetect path.
3.) Copy the config-file from /boot into kernel-sources as ".config", run a "make menuconfig" and make dep.
5.) Try to compile DVB-driver.
OK, i've done 1,3 and 5.
2 and 4 I don't know how to do but given that i'm using a fresh install of RedHat, i'd assume that they're both true. I certainly haven't updated the compiler or kernel sources since I installed Red Hat if that helps.2.) Check, that kernel-sources and binaries are the same and complete 4.) Check you use the same compiler and version kernel was compiled with.