From this TechFile, an administrator can:

Obtain important information on Veritas Replication Exec 3.1 Service Pack 1, Hot Fix 1, including its installation and use.

Download Replication Exec 3.1 Service Pack 1, Hot Fix 1
   
Replication Exec 3.1 SP1 HF1 includes the following new improvements and fixes

• Replication Exec is now better able to handle certain files being "padded out" with zeroes at the end of the physical disk cluster assigned to the file. This  condition occurred in rare periods of extensive I/O processing during dynamic replication.
• Replication Exec no longer hangs if a corrupted journal file is encountered. In the event that a corrupted journal file is encountered, Replication Exec will now cause the job to restart.
  
  

Installation notes:

This service pack requires an existing installation of Veritas Replication Exec 3.1 and is not a self contained version of the Replication Exec software.  
To install Replication Exec 3.1 SP1 HF1, the administrator will need the original Replication Exec 3.1 installation CD or access to the installation set if it is located on a network.  

Replication Exec 3.1 Service Pack 1 (SP1) is automatically installed with Replication Exec 3.1 SP1 HF1 and includes significant enhancements to Replication Exec 3.1. Before installing Replication Exec 3.1 SP1 HF1, review the related information on Replication Exec 3.1 Service Pack 1, contained in this TechPDF: http://support.veritas.com/docs/273055 

Installing Veritas Replication Exec 3.1 SP1 HF1
Installation on an existing Replication Exec 3.1 server: Symantec recommends a backup of the systems before proceeding.

1. Exit any Replication Exec Administration Consoles if open
2. Download Replication Exec 3.1 SP1 HF1 from the Download Now link of this TechFile
3. At each system running Replication Exec 3.1, starting with the computer hosting the Replication Management Service (RMS), run VRE31SP1HF1_281736.msp
Note: This is the default name of Replication Exec SP1 HF1 when it is downloaded from the Download Now link
4. Follow the instructions in the installation wizard to completion
5. Even in the absence of a prompt requesting a reboot, a reboot is required
Note:  If installing Replication Exec 3.1 SP1 HF1 in a clustered environment, special procedures must be followed. For the specific  procedures, see below

Steps to install Veritas Replication Exec (VRE) 3.1 SP1 on a cluster in Workgroup mode:
1. Insure that the VRE 3.1 installation is working correctly
2. Take any resources of type VRE Job offline
3. Take any resources of type VRE RMS offline
4. On the node that owns the storage containing the VRE RMS database, install the VRE 3.1 SP1 patch.  Allow the node to reboot.  It is very important that the storage containing the VRE RMS database be online and available to the VRE 3.1 SP1 patch software so that it can be properly upgraded.
5. Wait until the node reboots and reenters the cluster
6. Install the VRE 3.1 SP1 patch on any remaining nodes in the cluster.  Allow the nodes to reboot
7. Restart the VRE RMS resource
8. Run the VRE console to insure that the VRE RMS resource is indeed working correctly
9. Upgrade any nodes outside of the cluster to VRE 3.1 SP1.  Reboot these nodes and wait for them to come online
10. Bring any VRE Job resources online
At this point, the cluster has been upgraded.

Steps to install VRE 3.1 SP1 on a cluster in Domain mode
Note: This is the preferred upgrade method.  
1. Move all cluster service groups containing the VRE RMS or VRE Job resources to the same cluster node
2. Perform the following on every cluster node that does not own the VRE RMS or VRE Job resources:

a. Run the SP1 installer. Follow the prompts and allow the node to reboot
b. Run the Services Manager utility on the node and place the node in Domain mode. Despite being prompted, do not restart the services. Enter a valid set of credentials and follow the rules for the account used.
c. Run the SetIntegratedLogin utility on the node. Be sure to make a note of the password that is used. It must be the same that is used on every cluster node.

3. Take any VRE Job resources offline.  Since these resources are typically at the top of the resource tree, this should cause no interruption in service other than to replication.
4. Take the VRE RMS resource offline
5. Perform the general VRE 3.1 SP1 installation procedure discussed above. That is, run the SP1 installer on nodes outside the cluster that are participating in replication with the cluster and reboot them. Run the Services Manager to place each of these nodes into domain mode and restart the services. Run the SetIntegratedLogin utility to place each of these nodes into Integrated Login mode
6. Run the SP1 installation on the remaining cluster node (that owns the VRE resources), as follows. Allow the node to reboot

a. Move all cluster service groups containing VRE RMS and VRE Job resources back to the node that was just rebooted
b. Run the Services Manager on the remaining node, placing the node in domain mode. Despite being prompted, do not restart the services
c. Run the SetIntegratedLogin utility to place the remaining node into Integrated Login mode
d. Bring the VRE RMS resource online.  Wait for the resource to come online
e. Bring the VRE Job resources online  

At this point,  the SP1 process has finished and normal operations may resume

How to uninstall this hotfix
Once installed, this Replication Exec hotfix cannot be uninstalled.