My SHN and Flac plug-ins work on Ahead Nero Version 6.0.0.15
I guess that you saw the note:
Using The Plugins
* Nero Burning ROM version 5.5.9.0 or higher is required for all plugins.
* For Nero version 5, unzip the plugin DLL into "...\Ahead\Shared\AudioPlugins" directory.
* For Nero version 6, unzip the plugin DLL into "\Program Files\Common Files\Ahead\AudioPlugins" directory.
* The first two letters of the plugin DLL name must be "nx" in lower case, otherwise it won't be recognized by Nero Burning ROM.
DLL versions are:
1.0.0.32(nxMySHN.dll) for SHN (476 Kb)
1.0.0.33(nxMyFLA.dll) for FLAC (112 Kb)
Want MD5s on the DLL files ?
[EDIT]
The plug-ins can put gaps in the disk even when "No Pause Between Tracks" is selected.
I think that the FLAC plug is worse on this...... YMMV