Please don't use Backup/Restore Web based as it may or may not work properly on an average 1 out of 10 times it may work, but with command line it will work perfectly and I am composing step by step process to do backup/restore using command line.
Step 1: Start - Run - cmd -- cd\
Description: type cd\
Step 2: C:\> cd C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN
Description: type cd and put the above path i.e. 12 Hive
Step 3: C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN>
stsadm -o backup -url http://oldsite/ -filename mybackup.bak
Description: type backup command next to bin> and enter the following
-url "Enter url for sitecollection"
-Filename "Enter backupfile name with extension .bak
Step 4: C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN>
stsadm -o restore -url http://newsite/ -filename mybackup.bak -overwrite
Description: type restore command next to bin> and enter the following
-url "Enter new url for sitecollection"
-Filename "Enter backupfile name with extension .bak
-overwrite Inorder to overwrite existing structure and content
NOTE: Make sure that sitecollection http://newsite/ is already created.
I hope you will successfully do a backup/restore using command line and feel free to let me know for any questions.
