Hi,
First, you must run the update executable "as an administrator". So, right-click on the file then "Run as administrator".
Second, in the form you only need to have the installation folder before validating "Next".
So if the installation folder is "c:\wamp", this is what you need to see before pressing the "Next" button:
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Documentation Apache -
Documentation PHP -
Documentation MySQL -
Wampserver install files & addons