diff --git a/COMPILING b/COMPILING
index ca64df0d..495e84fe 100644
--- a/COMPILING
+++ b/COMPILING
@@ -18,6 +18,7 @@ To get a copy of the source using the commandline Subversion client:
   svn checkout -r29 https://zerowing.idsoftware.com/svn/radiant.gamepacks/Q3Pack/trunk/ ./GtkRadiant/games/Q3Pack
   svn checkout https://zerowing.idsoftware.com/svn/radiant.gamepacks/UFOAIPack/branches/1.5/ ./GtkRadiant/games/UFOAIPack
   For other game packs, see https://zerowing.idsoftware.com/svn/radiant.gamepacks/
+  Note that they must be in GtkRadiant 1.5's format (like the ones in a branches/1.5 subfolder)!