PostgreSQL terminated abnormally

We were successfully running PostgreSQL 8.0 on Win2003 for several
months without downtime.
Then suddenly PostgreSQL crashed and there were following info in log file

2005-10-09 03:51:10 WARNING: there is no transaction in progress

2005-10-09 03:51:10 WARNING: there is no transaction in progress

2005-10-09 03:51:24 PANIC: could not rename file "C:/Program
Files/PostgreSQL/8.0/data/pg_xlog/0000000100000000000000CD" to "C:/Program
Files/PostgreSQL/8.0/data/pg_xlog/0000000100000000000000D2" (initialization
of log file 0, segment 210): No such file or directory

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

2005-10-09 03:51:24 LOG: background writer process (PID 3448) was terminated
by signal 3

2005-10-09 03:51:24 LOG: terminating any other active server processes

2005-10-09 03:51:24 WARNING: terminating connection because of crash of
another server process

2005-10-09 03:51:24 DETAIL: The postmaster has commanded this server process
to roll back the current transaction and exit, because another server process
exited abnormally and possibly corrupted shared memory.

2005-10-09 03:51:24 HINT: In a moment you should be able to reconnect to the
database and repeat your command.

2005-10-09 03:51:24 WARNING: terminating connection because of crash of
another server process

2005-10-09 03:51:24 DETAIL: The postmaster has commanded this server process
to roll back the current transaction and exit, because another server process
exited abnormally and possibly corrupted shared memory.

2005-10-09 03:51:24 HINT: In a moment you should be able to reconnect to the
database and repeat your command.

2005-10-09 03:51:24 WARNING: terminating connection because of crash of
another server process

2005-10-09 03:51:24 DETAIL: The postmaster has commanded this server process
to roll back the current transaction and exit, because another server process
exited abnormally and possibly corrupted shared memory.

2005-10-09 03:51:24 HINT: In a moment you should be able to reconnect to the
database and repeat your command.

2005-10-09 03:51:24 WARNING: terminating connection because of crash of
another server process

2005-10-09 03:51:24 DETAIL: The postmaster has commanded this server process
to roll back the current transaction and exit, because another server process
exited abnormally and possibly corrupted shared memory.

2005-10-09 03:51:24 HINT: In a moment you should be able to reconnect to the
database and repeat your command.

2005-10-09 03:51:24 WARNING: terminating connection because of crash of
another server process

2005-10-09 03:51:24 DETAIL: The postmaster has commanded this server process
to roll back the current transaction and exit, because another server process
exited abnormally and possibly corrupted shared memory.

2005-10-09 03:51:24 HINT: In a moment you should be able to reconnect to the
database and repeat your command.

2005-10-09 03:51:24 LOG: all server processes terminated; reinitializing

2005-10-09 03:51:24 LOG: database system was interrupted at 2005-10-09
03:51:24 FLE Daylight Time

2005-10-09 03:51:24 LOG: checkpoint record is at 0/CE030078

2005-10-09 03:51:24 LOG: redo record is at 0/CE030078; undo record is at 0/0;
shutdown FALSE

2005-10-09 03:51:24 LOG: next transaction ID: 140670456; next OID: 3537664

2005-10-09 03:51:24 LOG: database system was not properly shut down;
automatic recovery in progress

2005-10-09 03:51:24 LOG: record with zero length at 0/CE0300B8

2005-10-09 03:51:24 LOG: redo is not required

2005-10-09 03:51:24 PANIC: could not rename file "C:/Program
Files/PostgreSQL/8.0/data/pg_xlog/0000000100000000000000CD" to "C:/Program
Files/PostgreSQL/8.0/data/pg_xlog/0000000100000000000000D2" (initialization
of log file 0, segment 210): No such file or directory

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

2005-10-09 03:51:24 LOG: startup process (PID 4184) was terminated by signal
3

2005-10-09 03:51:24 LOG: aborting startup due to startup process failure

2005-10-09 03:51:24 LOG: logger shutting down

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What are the reasons for this error?