Permission problem maybe???How To Use the Windows XP and Windows Server 2003 Registry Editor Features
has the following...
Assigning Permissions to a Registry Key
1. Click the key that you want to assign permissions.
2. On the Edit menu, click Permissions.
3. Click the group or user name that you want to work with.
4. Assign one of the following access levels to the key:
Select the Allow check box for Read to give permission to read the key contents, but not save any changes.
Select the Allow check box for Full Control to give permission to open, edit, and take ownership of the key.
5. To grant special permission in the key, click Advanced, and then double-click the user or group that you want to assign special access. Under Permissions, select the Allow or the Deny check box for each permission you want to allow or deny.