Shoutbox

You're using a wrong option set.
use it like this:

xml code:

---

<ResGroup>
<Restrictions>
<MsgVersions>
<Version Major="14" Minor="0"/>
</MsgVersions>
<SkinOptions>
<OptionSet>
<Conditions>CLBackground = "Mac"</Conditions>
</OptionSet>
</SkinOptions>
</Restrictions>
<Resources>
<Replace>
<Graphics>
<Pictures>
<Picture Id="625"><File>Background/Mac.jpg</File><Metadata><UMLeft>1</UMLeft><UMTop>1</UMTop><UMRight>1</UMRight><UMBottom>1</UMBottom></Metadata></Picture>
</Pictures>   
</Graphics>
</Replace>           
</Resources>
</ResGroup>

---