Hi Joe, we came across a rather obscure bug. Here are the reproduction steps (I verified it on demo.mojoportal.com):

1. Turn on "Allow Setting Skin For Page".
2. Set the site default skin to an Artisteer skin (tested with Artisteer-30alphamotors).
3. Set a page to use a non-Artisteer skin (tested with styleshout-envision on the home page).
4. From that non-Artisteer skin page, click the "New Page" button.

You will receive a server error page, and in the System Log is the below exception. We were able to work around this by putting a dummy script.js file into our styleshout-envision skin folder.

Thanks,
Jamie

2011-10-19 11:32:50,190 ERROR 10.1.100.53 - en-US - /Data/style/mojo1.css - mojoPortal.Web.Global - 192.168.1.10 /Data/style/mojo1.css Referrer(http://mysite.com/Error.htm?aspxerrorpath=/Admin/PageSettings.aspx) useragent Mozilla/5.0 (Windows NT 6.1; rv:7.0.1) Gecko/20100101 Firefox/7.0.1
System.Web.HttpException (0x80004005): Web resource '/Data/Sites/7/skins/styleshout-envision/script.js' was not found.
   at System.Web.Handlers.ScriptResourceHandler.RuntimeScriptResourceHandler.GetScriptResourceUrlImpl(List`1 assemblyResourceLists, Boolean zip)
   at System.Web.Handlers.ScriptResourceHandler.RuntimeScriptResourceHandler.System.Web.Handlers.IScriptResourceHandler.GetScriptResourceUrl(List`1 assemblyResourceLists, Boolean zip)
   at System.Web.Handlers.ScriptResourceHandler.GetScriptResourceUrl(List`1 assemblyResourceLists, Boolean zip)
   at System.Web.UI.CompositeScriptReference.GetUrl(ScriptManager scriptManager, Boolean zip)
   at System.Web.UI.ScriptManager.RegisterUniqueScripts(List`1 uniqueScripts)
   at System.Web.UI.ScriptManager.RegisterScripts()
   at System.Web.UI.ScriptManager.OnPagePreRenderComplete(Object sender, EventArgs e)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

I was able to fix this in my local copy so it will be fixed in the next release, in the meantime if anyone else encounters it I'll just tell them the workaround is put an empty file named script.js in the skin folder as you did.

Haven't been able to push changes to the repository for a few days due to some issue at codeplex, I have an open support ticket with them so hopefully it will be fixed soon.

Thanks,

Joe