problem spectrum theme css leftfold when adding background

HI there,

I have very strange issue with this spectrum theme. So, here we go. I install the theme. I change the background to a custom image. The thing is the <div class> “main title” and also <div class> “sidebar title” have folding elements at their end (in the css “leftFold” and “rightFold”). It seems that when i add backround there is problem with them – please see the image. The strange thing is that when i add the theme to the wordpress.com blog – there is no problem. When i add the image to my self-hosted blog – this happens. I will be very happy if anybody can give me some help. Thank you in advance !

Greeting