Hi Nicogrim, I've checked your QET schema and the problem is the logo at the title block.
The QET schema files are a XML type file, and the library I use in the Terminal Block plug-in requires that the XML file is well-formed.
If you get a error likes this : "xml.etree.ElementTree.ParseError: unbound prefix: line 8, column 20", open the qet schema file in a text editor and you will see this (line 8)
<ns0:svg ns1:version="0.46+devel" id="Livello_1" ns1:output_extension="org.inkscape.output.svgz.inkscape" viewBox="0 0 116 116" width="128" ns1:export-filename="/home/pinheiro/pics/oxygen-icons/scalable/apps/QElectroTech.png" overflow="visible" ns1:export-ydpi="67.5" xml:space="preserve" ns2:version="0.32" height="128" ns2:docname=" QElectroTech.svgz" enable-background="new 0 0 116 116" ns1:export-xdpi="67.5" version="1.0">
The "ns0" of the "ns0:svg" is a XML namespace ( https://www.w3schools.com/XML/xml_namespaces.asp ), and must be defined berefe the first use.
The easy wey to solve this is adding de namesapce definition in the first line:
Original first line:
<project folioSheetQuantity="1" title="CTA SBO 39CZ450" version="0.70">
Modified first line with the namespace definition:
<project folioSheetQuantity="1" title="CTA SBO 39CZ450" version="0.70" xmlns:ns0="ns0">
Specifically in your XML file there are 7 different namespaces used but not defined. So the solution is change the first line like this:
<project folioSheetQuantity="1" title="CTA SBO 39CZ450" version="0.70" xmlns:ns0="ns0" xmlns:ns1="ns1" xmlns:ns2="ns2" xmlns:rdf="rdf" xmlns:ns4="ns4" xmlns:dc="dc" xmlns:ns6="ns6">
The easy way to find all namespaces is fix one editing the first line, save it, and try again the plugin from the console. A new unbound error will say you where are a next namespace.
PD: I've checked the possibility that the ElementTree library I use in the plugin omits the namespaces, but didn't find the possibility.