Site backup in moss 2007 is not an rocket science anymore.
Download the tool Smigrate.exe from the Microsoft site.
extract under the Bin folder of the 12 hive.
pass the command
sMigrate.exe -w http://localhost/sites/Murugesan -f Murugesan1.fwp -u administrator -pw your password
Yes ! look at the command window for the status of the given command.