Out of variable data space!!!

Hi my problem directly refer to the title of the topic!
I just explain my application : I have a connection with the function serBgets() which collects strings comming from another serial, my problem is that i want to store the data in a char of 17000 bytes! So that’s why i get this error.
I read in the “yahoo user group for Rabbit Semi C-programmable microcontrollers” that i should use xmem but i don’t know how to use it.
Can someone tell me if it’s the best solution, or if there’s other solutions.
I don’t know if you’ll correctly understand me [ english is not my first language ]