I am currently trying to complete a transaction for a web based app, however;
Failed To Convert Parameter Value From A String To A Int32
I belive the problem is in your first paramter (storeCode). You're trying to send a string as an int paramter.
That line should read like this:
command.Parameters.Add("@storeCode", SqlDbType.Int).Value = Convert.ToInt32(storeCode);
There's one more suspicious thing: the parameter's name is storeCode, which implies a varchar column. What's the value you're trying to pass as a storeCode? Are you sure it's an int?