Well, this is clearly not Photomechanic's problem. It's a normal issue in Windows XP, where non-admin users are restricted from direct access to hardware. All other burners won't work unless you log in as admin.
This is what you can do to fix this:
I cannot write discs unless I'm logged in as Admin
* While logged in as administrator go to Start -> Run -> gpedit.msc
* Browse to Local Computer Policy, Computer Configuration, Windows Settings, Security Settings, Local Policies, Security Options
* Enable "Restrict CD-ROM access to locally logged-on user only".
This removes is the ability to use the CD-Rom as a Terminal Services client but allows any current user to write regardless of admin rights.
Note: If gpedit is not available (running XP Home for instance) and you are logged in with Admin permissions you may change the following value manually to achieve the same result.
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
"allocatecdroms"="1"