I am trying to change the skin of each tabs (filtered)  on given portal by using the following code : 

pid=484;

DesignController oDesignCtrl = new DesignController(); 

DesignInfo oDesign = oDesignCtrl.GetDesignDetail(did); 

if (oDesign != null) { DotNetNuke.Entities.Tabs.TabController oTabCtrl = new DotNetNuke.Entities.Tabs.TabController(); DotNetNuke.Entities.Tabs.TabCollection lstTabs = oTabCtrl.GetTabsByPortal(pid); System.Collections.ArrayList aryTabs = lstTabs.ToArrayList(); 

for (int i = 0; i < aryTabs.Count; i++) { DotNetNuke.Entities.Tabs.TabInfo oTab = (DotNetNuke.Entities.Tabs.TabInfo)aryTabs[i]; 

if (oTab != null) { 

if (!oTab.IsSuperTab && !oTab.IsDeleted && oTab.Level == 0) { 

oTab.SkinSrc = oDesign.SkinSrc; oTabCtrl.UpdateTab(oTab); 

}}}}

but its throwing following error :

...Default-Advance.doctype.xml' is a physical path, but a virtual path was expected. ---> System.Web.HttpException: 'C:/Inetpub/vhosts/[somefolder]/httpdocs/Portals/_default/Skins/[somefolder]/Default-Advance.doctype.xml' is a physical path, but a virtual path was expected. at System.Web.Util.UrlPath.CheckValidVirtualPath(String path) at System.Web.Util.UrlPath.Combine(String appPath, String basepath, String relative) at System.Web.VirtualPath.Combine(VirtualPath relativePath) at System.Web.HttpRequest.MapPath(VirtualPath virtualPath, VirtualPath baseVirtualDir, Boolean allowCrossAppMapping) at System.Web.HttpServerUtility.MapPath(String path) at DotNetNuke.Entities.Tabs.TabInfo.CheckIfDoctypeConfigExists() at DotNetNuke.Entities.Tabs.TabInfo.get_SkinDoctype() at DotNetNuke.Framework.DefaultPage.SetSkinDoctype() at DotNetNuke.Framework.DefaultPage.OnInit(EventArgs e) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---

So, i am not able to write a working code to change a skin for a page programmatically. I am stuck on it and no clue ,nothing on web anywhere , i google too but nothing found.

I really need some suggestion from experts. 

Thanks