Can we see how you configured the virtual path provider and the virtual path mappings?
My post explains an approach on how to override default EPiServer functionalilty:
Are you following this approach or doing something different?
i am getting the above error when I am trying to override WorkflowHistoryList.ascx using a virtual path provider. Has anyone else come across this and found a solution? Is there any more tried and tested way of making the workflow history list more user friendly