Thunar or Nautilus extension does not run, is there something special with my machine?

It is possible.

Some Linuxes detect the Nautilus extensions placed in $(HOME)/.nautilus/extensions-2.0, some Linuxes don't. In this case you have to place the extension in /usr/lib/nautilus/extensions-2.0 but it typically requires root privileges (simply copy or link to the libecmerge-nautilus.ext.so from /opt/elliecomputing/ecmerge directory).

Thunar never supported extension in $(HOME) directory, however, the folder in which the extension must be installed changed at some point (and their is not always a tool to return the installation directory). You may have to create the directory /usr/local/lib/thunarx-1 and place the libecmerge-thunar.ext.so file in there. It may be /usr/lib/thunarx-1 directory as well.