Oracle Database Discussions

Hello,
First post here...

I got an error that made 2 datafiles become offline. I had to recover them and it seems to work now.
I wonder what is the cause of that. My db (9i in Archivelog mode) is on a W2K Server.
Here is part of the alert.log:
-------------------------------------------------------------------------
Thu Apr 14 10:10:52 2005
Thread 1 cannot allocate new log, sequence 1132189
Checkpoint not complete
Current log# 3 seq# 1132188 mem# 0: L:\ORAHOME1\ORADATA\MYBASE\REDO03.LOG
Thu Apr 14 10:10:53 2005
Errors in file d:\orahome9i\admin\mybase\bdump\mybase_ckpt_5528.trc:
ORA-01171: datafile 29 going offline due to error advancing checkpoint
ORA-01122: database file 29 failed verification check
ORA-01110: data file 29: 'D:\ORAHOME1\ORADATA\MYBASE\MY_DATA_FILE.ORA'
ORA-01208: data file is an old version - not accessing current version
-------------------------------------------------------------------------
I have to precise that the datafiles are quite
small (ie <1GB) and that the problem occured during the production (not after any admin operation on the db).

The only preceding events that could be the cause of this problem, I think, are due to ARC process:
-------------------------------------------------------------------------
Thu Apr 14 10:10:49 2005
ARC0: Evaluating archive log 1 thread 1 sequence 1132186
ARC0: Warning. Log sequence in archive filename wrapped
to fix length as indicated by %S in LOG_ARCHIVE_FORMAT.
Old log archive with same name might be overwritten.
ARC0: Beginning to archive log 1 thread 1 sequence 1132186
Creating archive destination LOG_ARCHIVE_DEST_1: 'E:\ARCHIVELOGS_ORACLE\ARC32186.001'
ARC0: Completed archiving log 1 thread 1 sequence 1132186
-------------------------------------------------------------------------
I know that I should use %s instead of %S in my file mask.
But do you think that it could have been the origin of my problem ?

Thanks for any advice or idea to dig

Aurélien Bastardie