Good day.
We have begun working on a new site, based on the Construction template.
We used the Quickstart, added the Demo content and then added a second language (Greek), setting it as a default.
We published all the modules in the language specific menus and almost all of them work, except the Slideshow.
It takes up the space it's supposed to take but it doesn't show any of the demo content it's loaded with.
Upon inspection with Chrome, it shows an error that seems relevant:

uikit.min.js:24 Uncaught TypeError: Cannot read property 'addClass' of undefined
at Object. (uikit.min.js:24)
at Object. (jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at c (jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at Object.add [as done] (jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at Array. (jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at Function.each (jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at Object. (jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at Function.a.Deferred (jquery-migrate.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at Object.then (jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2)
at show (uikit.min.js:24)
(anonymous) @ uikit.min.js:24
(anonymous) @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
c @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
add @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
(anonymous) @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
each @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
(anonymous) @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
a.Deferred @ jquery-migrate.min.js?cb016252fee816c2cb8b9ed945af7843:2
then @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
show @ uikit.min.js:24
update @ uikit.min.js:24
init @ uikit.min.js:24
s @ uikit.min.js:2
(anonymous function) @ uikit.min.js:2
(anonymous) @ uikit.min.js:24
each @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
each @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
(anonymous) @ uikit.min.js:24
(anonymous) @ uikit.min.js:2
i.init @ uikit.min.js:2
(anonymous) @ uikit.min.js:2
dispatch @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
v.handle @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
trigger @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
a.event.trigger @ jquery-migrate.min.js?cb016252fee816c2cb8b9ed945af7843:2
(anonymous) @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
each @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
each @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
trigger @ jquery.min.js?cb016252fee816c2cb8b9ed945af7843:2
i.trigger @ uikit.min.js:2
e @ uikit.min.js:2

What have we done wrong and what can be done to correct it?

Thank you in advance,
Konstantinos Papadakis