Blank Multiterm entry, "firstChild" and helper.js error

When opening Multiterm, the term list displays just fine, but it's impossible to view or edit the entries. Only the Copyright mention is visible.

The entry content displays with the Default layout though.

When trying to edit or copy the entry, the following error appears:

The same error occurs in Studio in the terminology view.

I uninstalled both MT and Studio as well as Java and reinstalled everything, with no result. My guess is that my local configuration was changed, but I unfortunately can't retrace the changes... The "regsvr32 jscript.dll" didn't help either.

Any idea about this problem?