I am getting 500 error after applying changes to the Friendly urls settings under DNN host when using infinity urls module v 2.8.3 .

here is the error I am getting 

Url Master Processing Exception:Exception in Url Rewriting Process

Http Status:500 Internal Server Error

Url Master Version:2.8.3.0

Original Path:http://qualityborate.the-dev-server.com.192-185-7-207.secure10.win.hostgator.com/Home.aspx

Raw Url:/Home.aspx

Final Url:null

Rewrite Result:[no rewrite]

Redirect Location:[no redirect]

Action:Continue

Reason:Exception

Portal Id:0

Tab Id:-1

Http Alias:qualityborate.the-dev-server.com.192-185-7-207.secure10.win.hostgator.com

Debug Message 1:Exception: Object reference not set to an instance of an object.

Debug Message 2:(TRUNCATED TO 500 CHARS): Stack Trace: at DotNetNuke.Common.Globals.IsEditMode() at DotNetNuke.Entities.Tabs.TabModulesController.GetModules(TabInfo tab) at DotNetNuke.Entities.Tabs.TabModulesController.GetTabModules(TabInfo tab) at DotNetNuke.Entities.Tabs.TabInfo.get_Modules() at iFinity.DNN.Modules.UrlMaster.Entities.TabInfoEx.Clone(TabInfo tab) at iFinity.DNN.Modules.UrlMaster.Data.SqlDataProvider.GetTabs(Int32 portalId, Boolean includeAdminTabs, Boolean includeHostTabs, Dictionary`2& customAli

Debug Message 3:Inner Ex : null

Exception Type:System.NullReferenceException

Message:

Object reference not set to an instance of an object.

Stack Trace:(TRUNCATED TO 500 CHARS): at DotNetNuke.Common.Globals.IsEditMode() at DotNetNuke.Entities.Tabs.TabModulesController.GetModules(TabInfo tab) at DotNetNuke.Entities.Tabs.TabModulesController.GetTabModules(TabInfo tab) at DotNetNuke.Entities.Tabs.TabInfo.get_Modules() at iFinity.DNN.Modules.UrlMaster.Entities.TabInfoEx.Clone(TabInfo tab) at iFinity.DNN.Modules.UrlMaster.Data.SqlDataProvider.GetTabs(Int32 portalId, Boolean includeAdminTabs, Boolean includeHostTabs, Dictionary`2& customAliasTabs) a

I also tried X3 dnnurlmaster module https://dnnurlmanagement.codeplex.com but its not working . Inside custom redirect url under this module I added a custom url /AboutUs/tabid/72/Default.aspx (old site url) and added a 301 redirect to http://newdomainname.com/about-us but when I am visiting http://newdomainname.com/AboutUs/tabid/72/Default.aspx then its taking me to the file manager page under admin.

Please help me fix this issue asap.

Thanks

Pranav