BLD:W0052
Expression "%s" resolves to registry path (not allowed here)
The indicated expression resolves to a registry path, which is not allowed in this context. Although the expression expansion will succeed, the resulting value might not be valid for the context in which it is used and may cause the installation to fail.
Solution
You should check the indicated expression and make sure that it results in a value that is allowable in the context in which it is used.