crush with the RAY particles

Hello,

I would like to use the RAY particles sampled from a particular direction
distribution. However, my program, which works fine with normal projectiles,
crashes when I'm using it with RAY.
I get the message "Floating Exception" in the beginning of my .log file and
"Aborted (core dumped)" in its end.

In order to clarify the problem, I attach here the simplified source.f and
the input file.
In *source.f* I modified just these lines:
* Cosines (tx,ty,tz)
call sflood(x, y, z, cosX, cosY, cosZ)
XBEAM = x*100
YBEAM = y*100
ZBEAM = z*100
UBEAM = cosX
VBEAM = cosY
WBEAM = cosZ
and the input file is the same as $FLUPRO/example.inp without any
estimators.
If you intend to reproduce the problem, uncompress the tarball and type *make
run*.

Here is the gdb output:
Reading symbols from
/home/batkov/fluka/calet/MonteCarlo/ray-test/ray-test...done.
warning: Can't read pathname for load map: Input/output error.
Reading symbols from /usr/lib/libg2c.so.0...(no debugging symbols
found)...done.
Loaded symbols for /usr/lib/libg2c.so.0
Reading symbols from /lib/i686/cmov/libm.so.6...(no debugging symbols
found)...done.
Loaded symbols for /lib/i686/cmov/libm.so.6
Reading symbols from /lib/libgcc_s.so.1...(no debugging symbols
found)...done.
Loaded symbols for /lib/libgcc_s.so.1
Reading symbols from /lib/i686/cmov/libc.so.6...(no debugging symbols
found)...done.
Loaded symbols for /lib/i686/cmov/libc.so.6
Reading symbols from /lib/ld-linux.so.2...(no debugging symbols
found)...done.
Loaded symbols for /lib/ld-linux.so.2
Core was generated by
`/home/batkov/fluka/calet/MonteCarlo/ray-test/ray-test'.
Program terminated with signal 6, Aborted.
#0 0x4001e424 in __kernel_vsyscall ()
*(gdb) bt*
#0 0x4001e424 in __kernel_vsyscall ()
#1 0x400c68e0 in raise () from /lib/i686/cmov/libc.so.6
#2 0x400c9e15 in abort () from /lib/i686/cmov/libc.so.6
#3 0x4003819b in sig_die () from /usr/lib/libg2c.so.0
#4 0x40038229 in ?? () from /usr/lib/libg2c.so.0
#5 <signal handler called>
#6 0x4005db9e in ?? () from /lib/i686/cmov/libm.so.6
#7 0x40061110 in acos () from /lib/i686/cmov/libm.so.6
#8 0x0811465e in kasray_ () at kasray.f:167
#9 0x080fd19c in feeder_ (kendcn=0x95a05fc) at feeder.f:236
#10 0x0804d832 in flukam_ (iflgeo=0x85a3818) at flukam.f:3106
#11 0x080492e2 in MAIN__ () at fluka.f:290

Konstantin