Fat16/32 linking problems

Hi,
I have a little trouble with running Postgress on a embedded linux with
only Fat availible.
it runs for hours, but the it crashes and I cannot start it again.
Any Ideas ?

LOG:  database system was shut down at 2008-09-23 15:32:05 UTC
LOG:  checkpoint record is at 0/C4643C
LOG:  redo record is at 0/C4643C; undo record is at 0/0; shutdown TRUE
LOG:  next transaction ID: 2371; next OID: 25547
PANIC:  could not link file "/home/es4/pgsql/pg_xlog/xlogtemp.3438" to
"/home/es4/pgsql/pg_xlog/000000010000000000000001" (initialization of
log file 0, segment 1): Operation not permitted
LOG:  startup process (PID 3438) was terminated by signal 6
LOG:  aborting startup due to startup process failure



Jonny