Problem with Flashtool for Sony

[Mutak94]

Hello,
Does anyone know why can't I click on the arrow icon in the Flashtool? Other icons are grayed out too, here's a screen capture. Can anyone help me solve this problem because I cannot root my phone without these options (I'm following this tutorial to root my phone.
Thanks.

 

[Slug]

Ensure that "Enable USB Debugging" (Settings/Developer options) and "Allow installation from unknown sources" (Settings/Security) are both enabled.

If problems persist, try uninstalling the FlashTool/ADB drivers and reinstalling (see this link)