Hi Vineeth,
From my experience, the issue is mostly related to the permission of the user. In vista, we need to run the install package with elevated administrator permissions. In other words, the user has to have administrator permissions.
This link shows how to Marking the Privileges for an MSI:
http://msdn.microsoft.com/en-us/magazine/cc163486.aspx#S6.
I suggest not modify the registry keys in a custom action, we can directly add registry keys in Registry View of the Setup Project. If a registry key is added depending on a condition, we can set the condition property of the registry key.
Best regards,
Aland Li
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