First of all is G:/ a CDRW drive or a hard drive letter, if its the first try coping it to a section on your hard drive and then burning it from there. Unfortunatly XP can write data to CD-RW, but not directly from NTBackup. However, you can place backup files in the XP CD-RW write subsystem's spooler, which effectively writes the data directly to CD-RW. To add files to the spooler, perform the following steps:

Try following these steps:

1. Start NTBackup (go to Start, Programs, Accessories, System
2. Tools, and click Backup).
3. Select the Backup tab.
4. Select the files that you want to back up to CD-RW.
5. Select File for the type of "Backup destination."
Enter the following file location:

C:\documents and settings\<user name>\Local Settings\
Application Data\Microsoft\CD Burning\Backup.bkf

If you aren't sure what the <user name> variable needs to be, go to a command prompt and type
echo %userprofile% to check your %userprofile% environment setting.

6. After you specify the location of your files in the CD-RW
cache, right-click the "CD write" icon in Windows Explorer and select "Write these files to CD" to write the backup files to CD-RW.

Make sure the size of your backup doesn't exceed the capacity of your storage media.