llamar un webform de un button

[veliecer]

copie el codigo pero cuando corro el programa me sale un error al darle click algo como esto:

Server Error in '/ProcesaPrizesWEB' Application.
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The resource cannot be found.
Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly.

Requested Url: /ProcesaPrizesWEB/Redencion/CompraPuntos.aspx