This will probably be fixed in a later version of XnView.
- Zoom Player 4.03 also fails to play DivX 5 "packed bitstream" AVI files when DivX 6.0 codec is installed.
- Media Player Classic 6.4.8.4 has no problems playing DivX 5 "packed bitstream" AVI files with DivX 6.0 codec installed.
- Windows Media Player 9 instantly closes itself when trying to play DivX 5 "packed bitstream" AVI files with DivX 6.0 installed.
Step-by-Step Solution:
DivX Labs recommends setting DivX 6 Decoder to "Automatic Deblocking" only when using editing apps with DivX 6.
1. Open VirtualDub -> File Menu -> Open your DivX 5 "packed bitstream" AVI
2. Video Menu -> enable Full prcessing mode
3. Video Menu -> Compression... -> DivX 6.0 Codec (leave as default settings)
4. Audio Menu -> enable Direct Stream Copy
5. File Menu -< Save As -> Whatever filename you want
6. Click Save and Wait for the new non-packed AVI to be created

VirtualDub (freeware) can be downloaded here - http://www.virtualdub.org/
Notes:
Don't worry if the FourCC for the new AVI file still says DivX 5.0, as long as it plays in XnView it really doesn't matter.