Smart Rendering fails on one computer, works on the other

[tfolder]

Bit of a newbie question here. I have two laptops, let's call them A and B. Laptop A runs Windows 7 Starter 32-bit and laptop B runs Windows 8.1 64-bit but both have the same version of VirtualDub (x86) installed. I use laptop A for occasional editing of .mp4 files where I delete multiple segments from the middle and export to .avi using Fast Recompress/Smart Rendering. This works fine. But for some reason, when I try this with the exact same files on laptop B, I get this error:

"Cannot initialize smart rendering: The selected video codec is able to compress the source video, but cannot match the same compressed format."

I understand the idea behind Smart Rendering and what this error means. My problem is that I know basically nothing about identifying codecs or figuring out how to make VirtualDub use the right one. The Video > Compression settings on both laptops look exactly the same to me... I choose "x264vfw - H.264/MPEG-4 AVC codec" from the list and then see all the same information displayed in both cases, even on the Configure windows I can't spot any differences. I know laptop B has a newer version of K-Lite Codec Pack installed than laptop A (11.1.0 Mega vs. 7.0.0 Standard). Beyond that, I really don't know where to begin. Any help is appreciated (patient help, even more so ).

Typical mediainfo for the files in question:

Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 148 MiB
Duration : 49mn 7s
Overall bit rate mode : Variable
Overall bit rate : 420 Kbps

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L3
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 49mn 7s
Bit rate : 322 Kbps
Maximum bit rate : 1 143 Kbps
Width : 480 pixels
Height : 360 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 29.970 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.062
Stream size : 113 MiB (77%)
Tagged date : UTC 2014-03-03 19:44:32

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 49mn 7s
Bit rate mode : Variable
Bit rate : 96.0 Kbps
Maximum bit rate : 103 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 33.7 MiB (23%)

[sneaker]

Do you use the very same VirtualDub version on both systems? Do you use the same x264 VfW version on both systems? Is decoding disabled in the x264 VfW settings? Do you have an mp4 input plugin on system A but not on system B (any ".vdplugin" files in the VirtualDub folder on system A)?

[tfolder]

Well, I went looking for .vdplugin files and found only one on each system, QuickTime.vdplugin on A and FFInputDriver.vdplugin on B. I copied over the QuickTime plugin to laptop B and now everything seems to be working. So that was easier than I expected. Many thanks for pointing me in the right direction! It's been so long since I set up both systems (at different times) to actually *import* the mp4 files that I can't remember why I did them differently. I would've been following instructions I found online somewhere with only a general idea what I was doing. It's amazing they let noobs like me use serious tools like VirtualDub although, it has been handy on many occasions...