The patch release 1.0.6p1 fixes the following issues in 1.0.6:

MPICH2_NUMVERSION macro bug in mpi.h
bug in MPI_Gather
bug in MPD configure related to Totalview
some MPE bug fixes
fixes to timer code
snprintf prototype related bug in mpdroot.c
SMPD mpiexec rsh bug
ROMIO with PVFS2 linking bug
ROMIO ad_aggregate.c bug