Please help/ Belkin F5D6050 on Redhat 9.0

Hi,
     I am trying to make a Belkin F5D6050 wireless adapter work on Redhat 9.0 but have failed a few times.  I am using the driver  offered by   http://at76c503a.berlios.de/.  My computer has an ethernet card   for wired internet access, but I am not using it. My router is D-link 614+, which was configured on WinXP and works well under Windows, but I have not done anything to it on Linux (I think it is not needed, but not sure). The following is what I have done:

     First attempt:  on a Redhat 9.0 just installed.  I followed the readme in the at76c503a folder.
          make (fine)
          make install (fine)
          modprobe -v  at76c503-rfmd(error: modules compiled for kernel 2.4.20-8custom, while the kernel version is 2.4.20-8)
      
          Give up.

   Second attempt: I then compiled the kernel to get a custom version. And then follow the readme.
        make (fine)
        make install (error: depmod: cannot read ELF header from /lib/modules/2.4.20-8custom/kernel/drivers/usb/at76c503a.o/ depmod: unresolved symbols in ....a lot of files.../)
        modprobe -v at76c503-rfmd (fine, no info)
        iwconfig ....   (fine)
        ifconfig .... (fine)
        By "lsmod", I know all at76c503 modules are loaded. 
        Then I tried to ping google.com etc, nothing happened, and I still did not get wireless access.

       My questions are basically what steps I should do to get it work, which might include 
           Must I compile the kernel to get a customed one?
           What to do to deal with the errors in "make install"  mentioned above?
           If all succeeded up to "iwconfig, ifconfig", what else should I do before I finally get onto the net?
 
      I am really bad at these things, but I need to work on linux. Please help me out. Thanks a lot.

Sean