multiFormatsave does not work with LO

I can not get multiFormatsave to work on two computers with two different versions of LO. ONe computer is using Ubuntu 16.o4LTS and LP version 6.2,8.2 and the other uses Opp!_OS (based on Ubuntu 18.04LTS) with LO 6.3.4 and neither will allow multiFormatsave work.

I get the following message:
BASIC runtime error.
An exception occurred
Type: com.sun.star.container.NoSuchElementException
Message: .

Then LO displays the code for the extension.
I have communicated with the maintainer of the extension, and he has looked at his code for problems and can get it to work on his computers. He suggested that I contact LibreOffice and see if lyou can help.

… and you use which version of the extension downloaded from where?

Just tested that v.1.5.6 from Releases · ertaiNL/multiFormatSave · GitHub works fine on 6.4.0.2 x64 on Win10. A problem specific to Ubuntu? Please also specify how LibreOffice is installed on your systems: from distro repository; from PPA; using snap; from TDF DEB…?

Tested on Ubuntu 18.04, LibreOffice 6.3.4.2 from Launchpad PPA and MultiFormatSave 1.5.6 and that worked like a charm.

Update

Tested on Ubuntu 16.04, LibreOffice 6.2.8.2 from Launchpad PPA and MultiFormatSave 1.5.6 and that worked also