Getting an error while restoring logs in LOG SHIPPING environment

Question

Hello,

I'm working with SQL SERVER 2005 SP2.

I have a working and a steady environment of LOG SHIPPING for quite a while.

Yesterday, the Restore job of the LOG SHIPPING in the DR server failed with the locking error (the log starts from the last line and goes up):

05:02:38.34  *** Error: The log backup file 'C:\database\LogShipping\20100927021501.trn' was verified but could not be applied to secondary database ''
05:02:37.42  *** Error: Could not apply log backup file 'C:\database\LogShipping\20100927021501.trn' to secondary database ''.
05:02:37.42  *** Error: Exclusive access could not be obtained because the database is in use.
05:02:17.04  Restored log backup file. Secondary DB: ''<c/> File: 'C:\database\LogShipping\.trn'
05:00:01.01  Disconnecting users. Secondary DB: ''
05:00:00.64  Starting transaction log restore. Secondary ID: 'f89bba95-6fa8-4ee3-8883-3bb3b63f6127'<nl/>
05:00:00.64  Retrieving restore settings. Secondary ID: 'f89bba95-6fa8-4ee3-8883-3bb3b63f6127'<nl/>
05:00:00.65  Retrieved common restore settings. Primary Server: ''<c/> Primary Database: ''<c/> 
Backup Destination Directory: 'C:\database\LogShipping'<c/> File Retention Period: 4320 minute(s)<nl/>
05:00:00.65  Retrieved database restore settings. Secondary Database: ''<c/> Restore Delay: 0<c/> Restore All: True<c/> Restore Mode: Standby<c/> 
Disconnect Users: True<c/> Last Restored File: C:\database\LogShipping\20100927014500.trn<c/> Block Size: Not Specified<c/> Buffer Count: Not Specified<c/> Max Transfer Size: Not Specified
05:00:00.54  ----- START OF TRANSACTION LOG RESTORE  -----

The next restore job, succeeded with no issues, and it restore ALL the logs, even the older ones.

So What did it happen ?

I have the check-box "Disconnect Users in the Database when restoring backups" checked in the LOG SHIPPING Configuration.

You can see in the log above that there is a DISCONNECTING USERS stage.

In my Google searches, I only find links that tells me to check the above check-box, or to create a procedure that kills the sessions and run it prior the restore job.

But - there WAS a users disconnection prior the restore job. perhaps an applicative user tried to connect the DB in the fraction of a second between the end of the first log restoration and the second log restoration ?

If so, how can I prevent that from happening ?

Thanks, Roni.