diff --git a/makepanda/installer.nsi b/makepanda/installer.nsi
index 39b7dd3518..976bfd84f5 100644
--- a/makepanda/installer.nsi
+++ b/makepanda/installer.nsi
@@ -1239,8 +1239,13 @@ done:
 
 FunctionEnd
 
+!ifndef LVM_GETITEMCOUNT
 !define LVM_GETITEMCOUNT 0x1004
+!endif
+
+!ifndef LVM_GETITEMTEXT
 !define LVM_GETITEMTEXT 0x102D
+!endif
 
 Function DumpLog
   Exch $5