Hi,
Try stsadm.exe to take backup and restore the site.
Type the below lines in command prompt
For Backup:
1)CD C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN
2)stsadm.exe -o backup -url
http://your site path here -filename D:\backup.dat -overwrite
For Restore:
Copy that backup.dat file to the computer where you want to restore. ( I assume it is stored in D drive)
After that Type the below lines in command prompt
1)CD C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN
2)stsadm.exe -o restore -url
http://your site path here -filename D:\backup.dat -overwrite
After restore go to Central Administration page. In that click Application management menu. After that click Site collection Administrators which is under Sharepoint site management.
After that In primary site collection Administrator and secondary site collection administrator, you have to add the server administrator Id.