Kairn IR extender problem

Hi,

I bought a Marmitek IR control 8 extender set to operate my Kairn preamp whilst it's in a closed cabinet. The marmitek system responds to the kairn remote but the Kairn doesnt respond to the signal. Does anyone know whether or not these systems are compatible? The manual says it may not work with higher frequency systems but I m not sure the linn is. Btw, my old aristona cd player does respond when u use the linn remote with the marmitek system. Any thougts anyone?
Cheers