G Tech drive rebuild problem

I'm hoping you talented people can help. I have a G Tech Pro 1Tb raid in which one of the drives has failed. I have been running raid 3 so thankfully no data was lost. However my intel Mac will not load or display the gui to allow me to repair and rebuild the drive. A new 250gb drive has been installed in the mini tower, but no auto rebuild, and no way of doing so. The G Tech site has a foot note saying the config is not comparable with intel mac's!!
As this type of drive boots straight out of the box, the tech who installed it (long gone) didn't need to install the interface. But now I don't know how to rebuild it. Any help would be greatly appreciated.
My system is getting on a bit. Duel core 266ghz - 4gb ram running tiger 10.4.11