Google told me that this is a pretty well known error which can be fixed by setting the correct measurements for the selected country (duh

Went so far as to change Kilogram (dutch) to kilograms, and same for kg / kgs, tried pounds, etc. but no result. Well; if I change weight code "kgs" to "kg" I get another error stating "110546: kg is not a valid unit of measurement for weight for this shipment" so the weight code should be correct.
Same goes for measurement in size, tried virtually every combination but keep getting the error.
Long story short; I have no idea what to fix. If I could var_dump the results the OC extension sends and cross check those with UPS requirements I might find the solution, but I don't know how.
Anyone?