The hiex2dba error message (as displayed below).
* Error 3: exapi - BackupSetup
* HR [1293 / 50d]: Library not found!
* Error [1293/50d] setup backup
The reason may have been that esebcli2.dll (the Microsoft Exchange 2003/2007 Backup/Restore API DLL) is not in the PATH of the backup executing environment (agent service). For instance, if the Exchange server binaries are located in D:\Program Files\Exchsrvr\bin, then this path must be part of the PATH variable. You can check the content of the PATH variable by executing the "path" command in a DOS box.
Additionally try to change the logon user of the agent service of the exchange system to a user which has backup/restore permission with respect to Exchange.