Failure initialising EMSystem

Hi
While loading a game it shows error Failure initialising EMSystem. And try to add devicehigh=himem.sys n devicehigh=emm386.exe ram 2048 in config.sys. When reboot the system it shows Emm386 not install – unable to set page frame base address, and the game required 2560K of extended memory and shows that my system does not have enough memory to run it. But my system have 256M memory installed, can someone help me. Thx