Here are 2 logs, one from a burn that worked on a PC and one from a burn that didn't on my Mac:
Unsuccessful (MacBook) burn:
I 05:46:44 ImgBurn Version 2.5.1.0 started!
I 05:46:44 Microsoft Windows XP Professional (5.1, Build 2600 : Service Pack 3)
I 05:46:44 Total Physical Memory: 1,810,392 KB - Available: 1,344,072 KB
I 05:46:44 Initialising SPTI...
I 05:46:44 Searching for SCSI / ATAPI devices...
I 05:46:44 -> Drive 1 - Info: HL-DT-ST DVDRW GS21N SA18 (D:) (ATA)
I 05:46:44 Found 1 DVD±RW!
I 05:50:42 Operation Started!
I 05:50:42 Building Image Tree...
I 05:50:48 Checking Directory Depth...
I 05:50:48 Calculating Totals...
I 05:50:48 Preparing Image...
I 05:50:48 Checking Path Length...
I 05:50:48 Contents: 9 Files, 2 Folders
I 05:50:48 Content Type: DVD Video
I 05:50:48 Data Type: MODE1/2048
I 05:50:48 File System(s): ISO9660, UDF (1.02)
I 05:50:48 Volume Label: DIRTY_PRETTY_THINGS
I 05:50:48 IFO/BUP 32K Padding: Enabled
I 05:50:48 Region Code: 1, 2, 3, 4, 5, 6
I 05:50:48 TV System: NTSC
I 05:50:48 Size: 4,680,765,440 bytes
I 05:50:48 Sectors: 2,285,530
I 05:50:48 Image Size: 4,681,400,320 bytes
I 05:50:48 Image Sectors: 2,285,840
I 05:51:26 Operation Successfully Completed! - Duration: 00:00:44
I 05:51:26 Operation Started!
I 05:51:26 Source File: -==/\/[bUILD IMAGE]\/\==-
I 05:51:26 Source File Sectors: 2,285,840 (MODE1/2048)
I 05:51:26 Source File Size: 4,681,400,320 bytes
I 05:51:26 Source File Volume Identifier: DIRTY_PRETTY_THINGS
I 05:51:26 Source File Application Identifier: IMGBURN V2.5.1.0 - THE ULTIMATE IMAGE BURNER!
I 05:51:26 Source File Implementation Identifier: ImgBurn
I 05:51:26 Source File File System(s): ISO9660, UDF (1.02)
I 05:51:26 Destination Device: [1:0:0] HL-DT-ST DVDRW GS21N SA18 (D:) (ATA)
I 05:51:26 Destination Media Type: DVD-R (Disc ID: CMC MAG. AM3) (Speeds: 2x, 4x, 8x)
I 05:51:26 Destination Media Sectors: 2,297,888
I 05:51:26 Write Mode: DVD
I 05:51:26 Write Type: DAO
I 05:51:26 Write Speed: 2x
I 05:51:26 Link Size: Auto
I 05:51:26 Lock Volume: Yes
I 05:51:26 Test Mode: No
I 05:51:27 OPC: No
I 05:51:27 BURN-Proof: Enabled
I 05:51:27 Write Speed Successfully Set! - Effective: 2,770 KB/s (2x)
I 05:51:27 Filling Buffer... (40 MB)
I 05:51:29 Writing LeadIn...
I 05:52:35 Writing Session 1 of 1... (1 Track, LBA: 0 - 2285839)
I 05:52:35 Writing Track 1 of 1... (MODE1/2048, LBA: 0 - 2285839)
I 06:20:52 Synchronising Cache...
I 06:21:20 Exporting Graph Data...
I 06:21:20 Graph Data File: C:\Documents and Settings\A\Application Data\ImgBurn\Graph Data Files\HL-DT-ST_DVDRW_GS21N_SA18_WEDNESDAY-APRIL-28-2010_5-51_AM_CMC_MAG._AM3_2x.ibg
I 06:21:20 Export Successfully Completed!
I 06:21:20 Operation Successfully Completed! - Duration: 00:29:53
I 06:21:20 Average Write Rate: 2,693 KB/s (1.9x) - Maximum Write Rate: 2,809 KB/s (2.0x)
I 06:22:10 Close Request Acknowledged
I 06:22:10 Closing Down...
I 06:22:14 Shutting down SPTI...
I 06:22:14 ImgBurn closed!
----------------------------------------------------------------
Successful (PC) burn:
I 21:03:28 ImgBurn Version 2.5.1.0 started!
I 21:03:28 Microsoft Windows XP Home Edition (5.1, Build 2600 : Service Pack 3)
I 21:03:28 Total Physical Memory: 752,620 KB - Available: 338,468 KB
W 21:03:28 Drive D:\ (FAT32) does not support single files > 4 GB in size.
I 21:03:28 Initialising SPTI...
I 21:03:28 Searching for SCSI / ATAPI devices...
I 21:03:28 -> Drive 1 - Info: TOSHIBA DVD-ROM SD-R6012 1F34 (E:) (ATA)
I 21:03:28 Found 1 DVD-RW!
I 21:05:49 Operation Started!
I 21:05:49 Building Image Tree...
I 21:05:51 Checking Directory Depth...
I 21:05:51 Calculating Totals...
I 21:05:51 Preparing Image...
I 21:05:52 Checking Path Length...
I 21:05:52 Contents: 9 Files, 2 Folders
I 21:05:52 Content Type: DVD Video
I 21:05:52 Data Type: MODE1/2048
I 21:05:52 File System(s): ISO9660, UDF (1.02)
I 21:05:52 Volume Label: DIRTY_PRETTY_THINGS
I 21:05:52 IFO/BUP 32K Padding: Enabled
I 21:05:52 Region Code: 1, 2, 3, 4, 5, 6
I 21:05:52 TV System: NTSC
I 21:05:52 Size: 4,680,765,440 bytes
I 21:05:52 Sectors: 2,285,530
I 21:05:52 Image Size: 4,681,400,320 bytes
I 21:05:52 Image Sectors: 2,285,840
I 21:05:54 Operation Successfully Completed! - Duration: 00:00:05
I 21:05:55 Operation Started!
I 21:05:55 Source File: -==/\/[bUILD IMAGE]\/\==-
I 21:05:55 Source File Sectors: 2,285,840 (MODE1/2048)
I 21:05:55 Source File Size: 4,681,400,320 bytes
I 21:05:55 Source File Volume Identifier: DIRTY_PRETTY_THINGS
I 21:05:55 Source File Application Identifier: IMGBURN V2.5.1.0 - THE ULTIMATE IMAGE BURNER!
I 21:05:55 Source File Implementation Identifier: ImgBurn
I 21:05:55 Source File File System(s): ISO9660, UDF (1.02)
I 21:05:55 Destination Device: [1:0:0] TOSHIBA DVD-ROM SD-R6012 1F34 (E:) (ATA)
I 21:05:55 Destination Media Type: DVD-R (Disc ID: CMC MAG. AM3) (Speeds: 1x)
I 21:05:55 Destination Media Sectors: 2,297,888
I 21:05:55 Write Mode: DVD
I 21:05:55 Write Type: DAO
I 21:05:55 Write Speed: 2x
I 21:05:55 Link Size: Auto
I 21:05:55 Lock Volume: Yes
I 21:05:55 Test Mode: No
I 21:05:55 OPC: No
I 21:05:55 BURN-Proof: Enabled
I 21:05:55 Write Speed Successfully Set! - Effective: 2,822 KB/s (2x)
I 21:05:55 Filling Buffer... (20 MB)
I 21:05:57 Writing LeadIn...
I 21:07:18 Writing Session 1 of 1... (1 Track, LBA: 0 - 2285839)
I 21:07:18 Writing Track 1 of 1... (MODE1/2048, LBA: 0 - 2285839)
I 22:03:28 Synchronising Cache...
I 22:04:41 Exporting Graph Data...
I 22:04:41 Graph Data File: C:\Documents and Settings\Owner\Application Data\ImgBurn\Graph Data Files\TOSHIBA_DVD-ROM_SD-R6012_1F34_WEDNESDAY-APRIL-28-2010_9-05_PM_CMC_MAG._AM3_2x.ibg
I 22:04:41 Export Successfully Completed!
I 22:04:41 Operation Successfully Completed! - Duration: 00:58:46
I 22:04:41 Average Write Rate: 1,356 KB/s (1.0x) - Maximum Write Rate: 1,416 KB/s (1.0x)
I 04:48:27 Close Request Acknowledged
I 04:48:27 Closing Down...
I 04:48:27 Shutting down SPTI...
I 04:48:28 ImgBurn closed!