Well, now that I've done a bunch more testing with disks burned by nero and burned by imgburn, it looks like imgburn probably isn't the culprit, I think something is wrong with my DVD player.
Sorry for the false alarm. I'll post a log here just for reference:
I 16:39:47 ImgBurn Version 2.5.0.0 started!
I 16:39:47 Microsoft Windows Vista Enterprise x64 Edition (6.0, Build 6002 : Service Pack 2)
I 16:39:47 Total Physical Memory: 6,288,120 KB - Available: 5,048,524 KB
W 16:39:47 SPTD can have a detrimental effect on drive performance.
I 16:39:47 Initialising SPTI...
I 16:39:47 Searching for SCSI / ATAPI devices...
I 16:39:47 Found 1 DVD-ROM, 1 DVD-ROM/CD-RW and 1 DVD�RW/RAM!
I 16:40:16 Operation Started!
I 16:40:16 Source File: D:\DVDTMP\MSI_LIMITED_EDITION_DVD.ISO
I 16:40:16 Source File Sectors: 531,280 (MODE1/2048)
I 16:40:16 Source File Size: 1,088,061,440 bytes
I 16:40:16 Source File Volume Identifier: MSI_LIMITED_EDITION_DVD
I 16:40:16 Source File Volume Set Identifier: 385C9118
I 16:40:16 Source File Application Identifier: DVD Studio Pro:3.0.2, DSPInterface:306, DVDAuthoring:287, DVDBase:294(Encoder: 361), Oxygene:252
I 16:40:16 Source File Implementation Identifier: Apple Computer, Inc.
I 16:40:16 Source File File System(s): ISO9660, UDF (1.02)
I 16:40:16 Destination Device: [4:0:0] ASUS DRW-2014L1T 1.02 (F:) (ATA)
I 16:40:16 Destination Media Type: DVD-R (Disc ID: TYG02) (Speeds: 4x, 8x)
I 16:40:16 Destination Media Sectors: 2,297,888
I 16:40:16 Write Mode: DVD
I 16:40:16 Write Type: DAO
I 16:40:16 Write Speed: 4x
I 16:40:16 Link Size: Auto
I 16:40:16 Lock Volume: Yes
I 16:40:16 Test Mode: No
I 16:40:16 OPC: Yes
I 16:40:16 BURN-Proof: Enabled
I 16:40:32 Filling Buffer... (40 MB)
I 16:40:33 Writing LeadIn...
I 16:40:54 Writing Session 1 of 1... (1 Track, LBA: 0 - 531279)
I 16:40:54 Writing Track 1 of 1... (MODE1/2048, LBA: 0 - 531279)
I 16:44:16 Synchronising Cache...
I 16:44:29 Image MD5: 6ebba0c780787dcae6861db8efbcdc2e
I 16:44:29 Operation Successfully Completed! - Duration: 00:04:13
I 16:44:29 Average Write Rate: 5,260 KB/s (3.8x) - Maximum Write Rate: 5,576 KB/s (4.0x)
I 16:44:35 Close Request Acknowledged
I 16:44:35 Closing Down...
I 16:44:35 Shutting down SPTI...
I 16:44:35 ImgBurn closed!