Rooted SE X10 but RE tells me my device needs root?

Dec 4, 2010 at 5:56 PM

I've rooted my Sony Xperia X10 using z4root from the Android Market.  I confirmed that my device was rooted by installing BusyBox, TitaniumBackup, Superuser, and reconfirmed that I had (#) by using Android Terminal.  When I tried using the following command:

busybox mount -o rw,remount /system

I get a message "you must be root"

I don't get it...does this mean that my device is not "completely" rooted?  Any information would be lots of help right about now.