Copying the driver over most likely won't work as it would have been compiled for your Suse box.
You should download the source code for your driver: http://support.3com.com/infodeli/too...uxdownload.htm
Before installing the drivers:
Use 'lsmod' to show what modules are installed and look for something along the lines of 3c509 and remove it using 'rmmod <3c509 module name>'
Then extract the driver source somewhere, configure, make and install/modprobe it...the instructions for this and further steps should be bundled with the source, but as tredegar mentioned ealier, those drivers were only tested on a later version of redhat to yours so you might have some dependency issues, but then again, you might not.