First, did you do the initial system configuration for K3B when you first ran it? It should tell you if that's been done when you run it. Second, if a dialogue box pops up when you insert the DVD, then the system has recognized the drive. K3B should also recognize the drive. Click on the drive for information, it's the topmost listing in the left panel, then it will show the drive information. Does the drive's capabilities listed match what you know of it? Check in PCC > Hardware > Browse and Configure Hardware to see the drive listing from the system.
Do make an attempt to correct the locale problem. That particular locale (ANSI_X3.4-1968) isn't a common one. I've never seen it used. I don't think it's right. I'm not sure if it's causing your problem, but it could. You may have to ask on this forum for help with that specifically.