Hola migsantiago:
Gracias por contestar mi pregunta, hice lo que me dices, pero sigo sin poder compilar me manda un un mensaje de error que es el siguiente:
SIMULATION LOG
==============
Design: UNTITLED.DSN
Doc. no.: <NONE>
Revision: <NONE>
Author: <NONE>
Created: 31/05/06
Modified: 31/05/06
Compiling source files...
Build completed OK.
Compiling netlist...
Linking netlist...
Partition analysis...
Simulating partition 1
Animation started sucessfully...
PROSPICE Release 6.5 SP2 (C) Labcenter Electronics 1993-2002.
SPICE Kernel Version 3f5. (C) Berkeley University ERL.
Reading netlist...
Reading SPICE models...
Loading library 'ANALOGD.SML'
Loading library 'APEX.SML'
Loading library 'BURRBROWN.SML'
Loading library 'ELANTEC.SML'
Loading library 'FAIRCHLD.SML'
Loading library 'INTERSIL.SML'
Loading library 'LINTEC.SML'
Loading library 'NATOA.SML'
Loading library 'SUPERTEX.SML'
Loading library 'TECCOR.SML'
Loading library 'TEX101.SML'
Loading library 'TEX301.SML'
Loading library 'TEX3_1.SML'
Loading library 'TEX401.SML'
Loading library 'TEX5_1.SML'
Loading library 'VALVES.SML'
Loading library 'ZETEX.SML'
Building circuit...
Added GEARTH resistor for net #00023.
Added GEARTH resistor for net #00024.
Instantiating SPICE models...
[U1] AVR model release 6.4 SP0.
[U1] Loaded 512 bytes of persistent EEPROM data.
ERROR: [U1] Must specify file extension for PROGRAM property.
Warning: [U1] No program code loaded.
[DSIM] BOOT Error.
Real Time Simulation failed to start
Real Time Simulation FAILED.
Simulation FAILED due to fatal simulator errors.
y no se que es lo que esta fallando, perdona mi ignorancia, no se si me puedas orientar.
no se que que valores debo poner en esta ventana:

o en esta otra:

Pero me imagino que por aqui esta el error.
Gracias.