could not read, could not write, could not fsync, Windows 2000, PostgreSQL 8.0.1

We are running PostgreSQL 8.0.1 since last week and have these
messages in our PostgreSQL log file:

2005-02-10 10:27:19 FATAL: could not read block 38 of relation 1663/17269/16676: Invalid argument
2005-02-10 10:27:19 FATAL: could not read block 46 of relation 1663/17269/16676: Invalid argument
2005-02-10 10:27:19 FATAL: could not read block 50 of relation 1663/17269/16676: Invalid argument

16676 is table "pgdepend"

2005-02-14 12:19:46 FATAL: could not read block 7 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 20 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 22 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 14 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 18 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 24 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 8 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 19 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 11 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 21 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 25 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 23 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 13 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 9 of relation 1663/17269/1247: Invalid argument
2005-02-14 12:19:46 FATAL: could not read block 12 of relation 1663/17269/1247: Invalid argument

1247 is table "pgtype"

2005-02-16 10:48:26 ERROR: could not write block 61 of relation 1663/17269/16676: Invalid argument
2005-02-16 10:48:26 CONTEXT: writing block 61 of relation 1663/17269/16676

16676 is table "pgdepend"

2005-02-16 12:47:03 ERROR: could not write block 3 of relation 1663/17269/1614690: Invalid argument
2005-02-16 12:47:03 CONTEXT: writing block 3 of relation 1663/17269/1614690

We couldn't find what 1614690 is?

2005-02-18 05:32:06 LOG: could not fsync segment 0 of relation 1663/17269/1677179: Permission denied
2005-02-18 05:32:06 ERROR: storage sync failed on magnetic disk: Permission denied

...
2005-02-18 07:58:28 ERROR: storage sync failed on magnetic disk: Permission denied
2005-02-18 07:58:29 LOG: could not fsync segment 0 of relation 1663/17269/1677179: Permission denied

These two messages are repeated every seconds for almost 2.5 hours
Again, we couldn't find what 1677179 is?

We are on Windows 2000 Server, Service Pack 4 and
were successfully running PostgreSQL 7.4.1 before that.

We have done a vacuum, analyze and reindex on pgdepend and pgtype and restarted PostgreSQL
a few times, we had no problems doing that but the error messages are still there.

Is this normal and if not, how do we fix that?

Thanks
Jean-Pierre Pelletier

p.s.: We also have messages "FATAL: could not read from statistics collector pipe" approx. twice an hour.