Getting error message when I installed my new cdrom drive sec slave drive atapi incompatible what can I do please help

Try turning your computer off, unplugging it, and then remove and reseat cables that connect to it at all points. Motherboard end and CD ROM drive end. Turn it back on and see what happens. It is also possible that the jumpers may be set incorrectly. If they seem to be set correctly, try changing the sec slave drive to the secondary master and change the other to secondary slave if you have 2 cd rom drives.