Error: rtcontrib: fatal - incomplete ray value from rtrace

Dear Radiance users,

I am running calculation of grid of illuminance sensors and recently I have
got several times this error message:

rtcontrib: fatal - incomplete ray value from rtrace

Does anyone have had this before or do you have any suggestion where I
should look for mistakes, I guess there could be several reason for this
error, but I don't know where to start. The rtcontrib command is as
following. I have run this several times because I split the grid and run
more simulations, and it was without problems even running several parallel
simulations in same time using same octree. I am submitting calculations on
our cluster which operating on Sun machines and using GridEngine.

rtcontrib @parameters/vmx_illum.opt -f -bn Nkbins -fo -o
results/vmx_test_grid_illum/%s.vmx \
-b kbinW @parameters/west.modifier -b kbinS @parameters/south.modifier -I+
oct/model_vmx.oct < sensors/grid/vmx_grid_test_illum.pts

Thank you for any suggestions