Crash on secheduling Boot Time Defrag

This is with Defraggler v. 2.01.239 (latest at the moment), on a fully updated

Windows XP Pro SP 3. No obvious signs of malware (AVG did not report anything,

then I switched to Security Essentials and still nothing). The machine otherwise

performs fine.

When I select Run Once or Run Every Time option from Boot Time Defrag menu, I get a

Problem message box with following contents:

Defraggler was unable to schedule the Boot Time Defrag. Please make

sure you run Defraggler with administrative privileges.

After I click OK (the only button), Defraggler crashes.

The crash is most likely a bug, but I presume there is still a problem with

registry key permissions somewhere to trigger the message.

What registry key(s) does Defraggler access

when scheduling a boot time defrag? I'd need to check their permissions.