connecting an external CD/DVD drive

[elux]

I'm trying to connect an external CD/DVD writer, a Pioneer DVR-115D model, on my Mac Mini 1.5 GHz PPC G4 with 1GB memory and Mac OS X v10.4.11.

First, I updated for Quick Time 7.5 and later I tried to install the update for iDVD: 6.0.2; 6.0.3; 6.0.4 and 7.0.2, but a message appeared on the windows installation:
"You cannot install iDVD Update on this volume. An eligible iDVD application was not found in the location/Application/iDVD.app."

I cannot understand why this message appears, because actually there's a version of iDVD on my application's folder, a 5.0.1 version.

So, could you help me with this problem?

Thanks in advance

Lux