Hi, here is what I see, and this also shows how it was installed - just copy it to the scripting directory, and KiCad sees it and shows the button.
So that is a somewhat different way to launch it. But using Tools|External plugins gives the same result as the button (no dialog).
I now realise the date 2020-07-03 is that of the .kicad_pcb - not the python script - will look again for an update to InteractiveHtmlBom…
Version: (5.1.6)-1, release build
libcurl/7.66.0 OpenSSL/1.1.1d (Schannel) zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.1.1) nghttp2/1.39.2
Platform: Windows 7 (build 7601, Service Pack 1), 64-bit edition, 64 bit, Little endian, wxMSW
wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8)
OpenCASCADE Community Edition: 6.9.1
Compiler: GCC 9.2.0 with C++ ABI 1013