Aargh, they did it again. And before reading this remember it may be correct again next time.
Option 1: use Sigil (sigil-ebook dot com) to change "en" to "guw" in the workbook. Probably there is only one instance of the langue code that TB looks at, but I do not know which. So change all. I'll post a video of how to do that.
Option 2: directly in the database. Find the database and open with a browser (see suggestion in my signature below). In the Browse Data tab, select the table lmm_woorkbookregex. In the language column filter for 'en' and change those entries to 'eng' so they don't get lost, subsequently change all 'guw' entries to 'en' so the guw parameters get applied to your workbook. If you do this, you cannot import a real English workbook for now, unless you put it back.
Option 3: take the txt file you show, which starts with 'delete from...' Change all 6 occurences of 'guw' to 'en', store as a NEW txt file (in Wordpad, I choose Save as UTF-8 with BOM, but sometimes it works just as UTF-8) and execute as normal (Settings bottom right hand corner: klick >_ and proceed). Having the 2 files makes it fairly easy to switch if next workbook is different again.