Commented Issue: Couldnot delete worksheet [11376]

I am trying to delete first sheet from excel file like below
_Worksheet _wsh = (_Worksheet)shs.get_Item(1);
_wsh.Delete();
But it throws error. Am i doing something wrong pls guide.
Comments: ** Comment from web user: tonyqus **

I never see this exception before. I'm afraid I cannot help.