vCenter 5.1b inventory service backup failed

Hi there

We have several vCenter 5.1b inventory services servers. When we use the backup.bat file located in C:\Program Files\VMware\Infrastructure\Inventory Service\scripts to generate inventory services backups we get the below errors

[2013-05-20 17:10:45,032 main  INFO  com.vmware.vim.dataservices.BackupDb] Starting Inventory Service backup script

[2013-05-20 17:10:45,063 main  INFO  com.vmware.vim.dataservices.BackupDb] Backing up Inventory Service data to: C:\Program Files\VMware\Infrastructure\Inventory Service\scripts\backup.DB

[2013-05-20 17:10:45,095 main  INFO  com.vmware.vim.dataservices.BackupDb] Connecting to Inventory Service...

[2013-05-20 17:10:45,845 main  ERROR com.vmware.vim.dataservices.BackupDb] Error: IO_ERROR, Original message: Software caused connection abort: recv failed

[2013-05-20 17:10:45,845 main  ERROR com.vmware.vim.dataservices.BackupDb] Backup failed

Does anyone know wheat causes this. In all instaces the vCenter inventory services are running with no errors, we are just unable to back them up.