Ok, that has nothing to do with long paths.
With which command exactly did you create the extension? In new bundling environments the build_python_extension.py does not provide the whole environment anymore. Instead, during installation it tries to download all the packages necessary.
We can check which one is the case: have a look at the size of org.finiti.panel_builder.channel.bin.win32.......:
- Some hundred MB? Then it should have been bundled with an older bundling environment and we need to investigate further.
- Some 5-30MB? Then there is no complete environment shipped with it and it cannot be installed on a computer without internet access.
For the second scenario, you can bundle it again with build_python_extension.py --include-packages --knime-version 5.1 <path/to/extension> <path/to/destination>. Have also a look at build_python_extension.py --help.
Does that work for you?
Best regards
Steffen