sorry, I had overlooked the hint to post the logs. here goes:
//****************************************\\
; ImgBurn Version 2.5.1.0 - Log
; Saturday, 21 August 2010, 18:03:31
; \\****************************************//
;
;
I 17:53:05 ImgBurn Version 2.5.1.0 started!
I 17:53:05 Microsoft Windows XP Professional (5.1, Build 2600 : Service Pack 2)
I 17:53:05 Total Physical Memory: 2,091,216 KB - Available: 1,739,536 KB
W 17:53:05 Drive D:\ (FAT32) does not support single files > 4 GB in size.
I 17:53:05 Initialising SPTI...
I 17:53:05 Searching for SCSI / ATAPI devices...
I 17:53:05 -> Drive 1 - Info: PIONEER DVD-RW DVR-112D AC08 (E:) (ATA)
I 17:53:05 -> Drive 2 - Info: HL-DT-ST DVDRAM GSA-E40L SE02 (H:) (USB)
I 17:53:05 Found 1 DVD±RW and 1 DVD±RW/RAM!
I 17:54:05 Operation Started!
I 17:54:05 Source File: C:\windows7x64.iso
I 17:54:05 Source File Sectors: 1,582,577 (MODE1/2048)
I 17:54:05 Source File Size: 3,241,117,696 bytes
I 17:54:05 Source File File System(s): None
I 17:54:05 Destination Device: [0:0:0] HL-DT-ST DVDRAM GSA-E40L SE02 (H:) (USB)
I 17:54:05 Destination Media Type: DVD-R (Disc ID: CMC MAG. AM3) (Speeds: 4x, 8x, 16x)
I 17:54:05 Destination Media Sectors: 2,297,888
I 17:54:05 Write Mode: DVD
I 17:54:05 Write Type: DAO
I 17:54:05 Write Speed: MAX
I 17:54:05 Link Size: Auto
I 17:54:05 Lock Volume: Yes
I 17:54:05 Test Mode: No
I 17:54:05 OPC: No
I 17:54:05 BURN-Proof: Enabled
I 17:54:05 Write Speed Successfully Set! - Effective: 22,159 KB/s (16x)
I 17:54:05 Filling Buffer... (40 MB)
I 17:54:05 Writing LeadIn...
I 17:54:49 Writing Session 1 of 1... (1 Track, LBA: 0 - 1582576)
I 17:54:49 Writing Track 1 of 1... (MODE1/2048, LBA: 0 - 1582576)
I 17:58:30 Synchronising Cache...
I 17:58:41 Exporting Graph Data...
I 17:58:41 Graph Data File: C:\Documents and Settings\plop\Application Data\ImgBurn\Graph Data Files\HL-DT-ST_DVDRAM_GSA-E40L_SE02_SATURDAY-AUGUST-21-2010_17-54_CMC_MAG._AM3_MAX.ibg
I 17:58:41 Export Successfully Completed!
I 17:58:41 Operation Successfully Completed! - Duration: 00:04:35
I 17:58:41 Average Write Rate: 14,387 KB/s (10.4x) - Maximum Write Rate: 19,369 KB/s (14.0x)
I 17:58:41 Cycling Tray before Verify...
W 17:58:51 Waiting for device to become ready...
I 17:59:07 Device Ready!
I 17:59:09 Operation Started!
I 17:59:09 Source Device: [0:0:0] HL-DT-ST DVDRAM GSA-E40L SE02 (H:) (USB)
I 17:59:09 Source Media Type: DVD-R (Book Type: DVD-R) (Disc ID: CMC MAG. AM3) (Speeds: 4x, 8x, 16x)
I 17:59:09 Image File: C:\windows7x64.iso
I 17:59:09 Image File Sectors: 1,582,577 (MODE1/2048)
I 17:59:09 Image File Size: 3,241,117,696 bytes
I 17:59:09 Image File File System(s): None
I 17:59:09 Read Speed (Data/Audio): MAX / MAX
I 17:59:09 Verifying Session 1 of 1... (1 Track, LBA: 0 - 1582576)
I 17:59:09 Verifying Track 1 of 1... (MODE1/2048, LBA: 0 - 1582576)
I 18:02:52 Exporting Graph Data...
I 18:02:52 Graph Data File: C:\Documents and Settings\plop\Application Data\ImgBurn\Graph Data Files\HL-DT-ST_DVDRAM_GSA-E40L_SE02_SATURDAY-AUGUST-21-2010_17-54_CMC_MAG._AM3_MAX.ibg
I 18:02:52 Export Successfully Completed!
I 18:02:52 Operation Successfully Completed! - Duration: 00:03:43
I 18:02:52 Average Verify Rate: 14,257 KB/s (10.3x) - Maximum Verify Rate: 19,639 KB/s (14.2x)
I 18:03:31 Close Request Acknowledged
I 18:03:31 Closing Down...
I 18:03:31 Shutting down SPTI...
I 18:03:31 ImgBurn closed!