problemas (ajuda)

olá galera, estou tentando aprender sobre o proteus, mas tive uns problemas resolvendo o tutorial, e apareceu o seguinte erro:
SIMULATION LOG
==============
Design: UNTITLED.DSN
Doc. no.: <NONE>
Revision: <NONE>
Author: <NONE>
Created: 22/10/09
Modified: 22/10/09

Compiling source files...
Build completed OK.
Compiling netlist...
Linking netlist...
Partition analysis...

Simulating partition 1 [0BA2466D]...
Animation started sucessfully...
PROSPICE Release 6.2 SP0 (C) Labcenter Electronics 1993-2002.
SPICE Kernel Version 3f5. (C) Berkeley University ERL.

Reading netlist...
Reading SPICE models...
Building circuit...
Added GEARTH resistor for net #00006.
Added GEARTH resistor for net #00007.
Added GEARTH resistor for net #00008.
Added GEARTH resistor for net #00009.
Added GEARTH resistor for net #00004.
Added GEARTH resistor for net #00005.
Instantiating SPICE models...
Warning: [SPICE] singular matrix: check nodes TR1_L1:A#branch and TR1_L1:A#branch

[SPICE] starting Gmin stepping
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
[SPICE] One successful Gmin step
Warning: [SPICE] singular matrix: check nodes TR1_L1:A#branch and TR1_L1:A#branch

Warning: [SPICE] Gmin stepping failed
[SPICE] starting source stepping
Warning: [SPICE] singular matrix: check nodes TR1_L1:A#branch and TR1_L1:A#branch

Warning: [SPICE] source stepping failed
[SPICE] Error 102 - (null).Real Time Simulation failed to start

Real Time Simulation FAILED.

E não compreendi o que está errado, alguem poderia me ajudar?? obrigado