several things can cause the following message:
Subroutine Unknown:0:ERROR
Your architecture is not able to handle 8, 4 or 2-bytes FORTRAN file record markers !
You cannot use ABINIT and MPI/IO.
1) incompatible versions of mpi, between the library you linked with, the one you have loaded at execution time, and some recent versions of (open)mpi are a bit buggy.
2) missing input file for wavefunctions or density. There is no clear error message, but this can get the mpi io into a fit and hang the job
3) incompatible number of k-points/bands/fft wrt the number of processors you provide, which should be a divisor of nkpt in the default parallelization, and must be an exact divisor of np_kpt*np_band*np_fft in the general paral_kgb case.
Try running in sequential or with fewer processors to see where the problem might be, or link to an older version of mpi (1.2.6 is usually ok)
See associated posts by Jean-Michel:
http://forum.abinit.org/viewtopic.php?f=3&t=1316
http://forum.abinit.org/viewtopic.php?f=3&t=1387
You should also check the tmp_XXX_LOG_P001 002 003 files, which log the errors from each processor. They will give you additional hints.
cheers
Matthieu