surface with ID xxxx,failed to load?(in 0.6.0012)

[LaoyeChan]

i have just updated my grasshopper to 0.6.0012 and when i set one
surface in rhino it said "surface with ID xxxx failed to load"But i
was able to load it in the latter version of gh before. What's the
problem with it?
see the pic here:http://groups.google.com/group/grasshopper3d/web/
error.bmp
thank you.