When you have an issue in one browser but not in another one, the next step would be to validate the HTML and CSS code at w3.org . I would not spend too much time on this issue if I were you, it is irelevant unless your purpose is to research differences between HTML and XHTML.
Have you tried different skins? I can hardly imagine you plan to use the minimal entropy skin on your final web portal. This skin is a demo skin in XHTML. If you plan to create a web portal in Arab, you will want some skins that are adapted to the right to left writing style, I suppose.
Try 3 different skins, clearly identifiable (for instance by different colors). Make one the default skin in the portal settings and the 2 other skins the default skin in each of the languages in the portal localization control. Before you go check your localized pages, clear the DSL cache (in the host section of the DSLocalizator module) if you told DSLocalizator to use cache (on the same place).
Then let me know what happens.
While you are at it, try to add a DSLocaleSelector module to one of your pages. Then click on the Locale Selector options in the module's action menu and try to configure it to your taste. Later on, I will explain how this module helps you to build a language selector in your skin.
Creating skins requires some knowledge of HTML and CSS. If you have this, creating a skin is much easier than it would seem at first. Tiendaboliviana is not the site to learn skinning, but if you do an effort to grasp some of the skinning techniques, I will show you how to use the LocaleSelector skin object in your skin.
By the way, the language selector in your minimal entropy skin is not DSLocaleSelector but the core Language skin object. It however functions just as well as DSLocaleSelector in a DSL environment. In former versions of DNN, the language skin object had very little options for configuration, whereas DSL was fully configurable with templates. But the latest versions of DNN have added new parameters to the language object. The only difference is now that DSL delivers smaller flags than DNN (which is one of the reasons that I continue to use it)