The use of "kindly" as in, "Kindly update us on the issue." is idiomatically a mildly pejorative phrasing in the United States generally. You would do well to substitute the word "please" for "kindly".
Was the replaced disk on the BEX server? If so, did it contain the BEX catalogs?Assuming you have all the data you need on tape and no catalogs on disk, you may be facing a reinstall of BEX V10, cataloging the appropriate tape and drilling down from...
Local or remote disk? iSCSI disk? Does BEX create a catalog to the file level of the data being backed up? When you attempt a restore are you able to select down to the last file backed up?
If you need to avoid a reboot you can also try stopping/restarting the BEX services on the system logging failures plus stopping/restarting the services on the BEX server. Sometimes one or the other resolves problems.