diff --git a/dlls/msi/custom.c b/dlls/msi/custom.c
index 12fe53ead10..72c3efd75a9 100644
--- a/dlls/msi/custom.c
+++ b/dlls/msi/custom.c
@@ -496,10 +496,10 @@ UINT __wine_msi_call_dll_function(const GUID *guid)
     RPC_WSTR binding_str;
     MSIHANDLE hPackage;
     RPC_STATUS status;
+    LPWSTR dll = NULL;
+    LPSTR proc = NULL;
     HANDLE hModule;
     HANDLE thread;
-    LPWSTR dll;
-    LPSTR proc;
     INT type;
     UINT r;