This is the message, when the file is broken!
QET saves it's data in XML-files and (like many others!) does not show where the problem might be, when loading fails.
Try to open a copy of that file (renamed to *.xml) with firefox: It shows the first problematic part, that you have to fix. This might have to be repeated several times, before the XML is valid.
In a CMD-Window you can also use the most recent version of QET_ElementScaler, where the first problematic part of the file will be shown:
usage:
QET_ElementScaler SchematicFile.qetIt might show something like this:
$ QET_ElementScaler filtre-à-bande.qet
File "filtre-à-bande.qet" could not be loaded: Error parsing element attribute
Check file up to byte-offset: 1196545 -- content partly shown here:
(...)rmula="" y="-130" numsize="7" condsize="1" conductor_colo" condsize="1" freezeLabel="false" bus="" dash-size="2" y="(...)
$