Does anyone know if this is a common problem? (Weird transparent header glitch)

Hey WP-gurus,

I downloaded a theme called Arvo from Elements, and up until now it’s been great. However, as soon as I started making a Revolution Slider, I began running into header issues. As seen in these screenshots, my header background appears to be underneath the slider, so it’s turning transparent (and pretty much invisible) when I start to scroll down. Is this a common issue? I don’t have support with Elements themes, so I thought I’d ask here in case someone knows a fix.

Cheers,

James / AA