Fluka crashes for higher primaries for heavy ion

Dear Fluka experts,

I was trying to get an LET spectrum from 956 MeV/n Fe beam behind aluminium
shield using an gas filled detector. For heavy ion, I used *flukadpm3
*executables
(I am not sure if I am right). Using FLAIR, I can run this input for 1000
primaries but if I increase the primaries (e.g. 10,000) it finishes with
error. If I don't use any executables this input runs fine even for higher
primaries but that is not what I want. I tried this in several computers
but I did not succeed. Could any one please suggest me how can I run this
input for higher number of primaries (10^6 at least). I Vastly appreciate
any kind of help. Attached is the input.

Sincerely
Mohammad
Physics dept, Oklahoma State University
  USA