ERROR occuring during pack in a gts surface

hi, i 'm facing some problems trying to pack in a gts surface.
 i had a repaired STL file(converted later in GTS). At first i couldn't use it becouse Yade said that the surface wasn't closed. I repaired it but it's not oriented. I already have the surface where i want it to be and oriented in the asked direction.

If i run : "vol = surf.volume()" it returns the error that the surface is not oriented.
-> is this a problem for the packing ? will it give me problem in the future?

When i try to run the code for the packing i got this error message:
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FATAL /build/yade-2_s9R0/yade-1.20.0/core/ThreadRunner.cpp:30 run: Exception occured:
Unable to shring cell due to maximum body size (although required by stress condition). Increase particle rigidity, increase total sample dimensions, or decrease goal stress.
ERROR /build/yade-2_s9R0/yade-1.20.0/py/wrapper/yadeWrapper.cpp:608 wait: Simulation error encountered.
Traceback (most recent call last):
  File "/usr/bin/yade", line 182, in runScript
    execfile(script,globals())
  File "TENTATIVO2.py", line 33, in <module>
    sp = pack.randomDensePack(pred,radius=0.01,spheresInCell=10)
  File "/usr/lib/i386-linux-gnu/yade/py/yade/pack.py", line 458, in randomDensePack
    O.run(); O.wait()
RuntimeError: std::exception

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i'm trying to change the randomdensePAck parameters ( radius and spheresincell) and material parameters, but the error doesn't change.

 I provide the script concerning the packing point (tell me if you need also the gts file). Really thanks for your time.

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surf = gts.read(open('RIPARATO.gts'))
pred=pack.inGtsSurface(surf,noPad=True)
#vol = surf.volume()

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##aereo material##
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idCA=FrictMat(density=1000,frictionAngle=radians(0.5),label='CA',young=30e7,poisson=0.15)
O.materials.append(idCA)

O.bodies.append(pack.gtsSurface2Facets(surf,color=(0,0,1)))
sp = pack.randomDensePack(pred,radius=0.03,spheresInCell=10)
sp.toSimulation()
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