Nero 5.5.5.1 permissions in WinXP

I have just loaded the trial version of Nero 5.5.5.1 into my windows XP system. On loading the program, I get an error message saying that under 2000/NT I have to have permission to access CD-R drives before it will recognise the drive and to contact the system administrator. I am logged in as administrator, so I do not know what to do. The drive is not recognised by Nero, although the file copy in Windows Explorer works well, as does Easy CD creator, which I tried after uninstalling Nero. My drive is a Plextor 1610 which has previously worked well with Nero 5.5.3.0 (which also gave me the same error message).

Does anybody know what I should do to give the program rights to access the CD-R drive?

Thanks

Frankie