Lotus Notes Database data corruption usually occurs when the software application or the operating system crashes while the .OND data file is open in memory. In most cases, headers or parts of the data file are not saved to disk causing the data corruption or the application to fail. There are ways to recover all or part of your data file. U should immediately make 2 or 3 backup copies of the corrupted OND file(s) and stop using the computer except to send the file(s) for recovery analysis. There is a very good tool “Stellar Phoenix Lotus Notes Recovery v2.0” such a tool is powerful that repairs & Recovers Lotus Notes NSF file & restores them in original format to any user-intended location.
Though I am providing a step by step, as my experience and recommended by IBM….
1. Make a new copy of the database and deselect Access Control List in the “Specify What to Copy” section of the Copy Database dialog box. This will bypass the corrupt ACL and create a default ACL that you can then modify as necessary.

2. Replace the design of a mail database with a non-mail template and then do a replace back to the mail template, which has been known to correct corrupted ACLs.

3. From the Administration client > Files tab, select a healthy ACL database where the ACL is similar to the one that needs to be replaced. Right-click and select ACL.Copy. Select the bad ACL database then right-click and select ACL.Paste. This is an easy way to reset the ACL.

U may try to download and repair to link http://www.officerecovery.com/lotusnotes/download_demo.htm

If all are failed, then go to ur Lotus dir and search for data directory and take full backup of archieve directory.

Hope this may help u !