Yeah, I've been having this problem recently...
Whenever I try to burn an ISO file on to a dvd+r dl disk it starts then it just gets stuck at "Performing Optimum Power Calibration" or something like that. I've even waited an hour before and it was still at that same step.
Thing is, I've burned an ISO file before onto a dl disk and it worked perfectly fine, same burner and everything.
Here's a log if it helps:
; //****************************************\\
; ImgBurn Version 2.4.0.0 - Log
; Sunday, 17 February 2008, 19:28:23
; \\****************************************//
;
;
I 19:28:17 ImgBurn Version 2.4.0.0 started!
I 19:28:17 Microsoft Windows Vista Home Premium Edition (6.0, Build 6000)
I 19:28:17 Total Physical Memory: 2,029,568 KB - Available: 1,131,376 KB
I 19:28:18 Initialising SPTI...
I 19:28:18 Searching for SCSI / ATAPI devices...
I 19:28:18 Found 1 DVD±RW/RAM!
I 19:28:23 Close Request Acknowledged
I 19:28:23 Closing Down...
I 19:28:23 Shutting down SPTI...
I 19:28:23 ImgBurn closed!
EDIT: just to let you know I'm a noob at burning