Run DES in pic18f2550

I'm going to run DES code(C language) on the PIC18F2550 microcontroller.For this I am using mplab IDE v 8.92 and Mplab c18 v 3.46.When I compile the code I get this error
MPLINK 4.48, Linker Device Database Version 1.13 Copyright (c) 1998-2011 Microchip Technology Inc. Error - section '.idata_des.o' can not fit the section. Section '.idata_des.o' length=0x00000540 Errors : 1
What is this error? How to fix?
Attention: when i use MPLAB X IDE v2.00 with xc8 v 1.30 I have no error!!!

.idata is the initialized data section. The error message indicates that there are more variables than can fit into the default section. One solution is to use #pragma idata "section name" ahead of groups of initialized variables. Each group must use 256 or fewer bytes of memory. XC8 may automatically take care of this (compiler generated psect).