Handle the indexerror exception on create_order

LMS-2646
Looks good, thanks for the change. One this is I would always recommend wrapping your lines when they get long like this, it makes things easier to read. You can do
```html
<p>
    ${_("blah blah "
        "blah blah blah "
        "blah blah blah")}
</p>
```
to effectively wrap lines in Mako templates.

Not required but is a general style recommendation.