diff -r aefd1576ce67 -r c2b3ed520d2b code/ryzom/tools/patch_gen/patch_gen_common.cpp
--- a/code/ryzom/tools/patch_gen/patch_gen_common.cpp	Mon Jun 21 23:06:34 2010 +0200
+++ b/code/ryzom/tools/patch_gen/patch_gen_common.cpp	Wed Jun 23 08:18:25 2010 +0300
@@ -375,7 +375,7 @@
 
 				// delete the previous patch - because we only need the latest patch for non-incremental files
 				std::string lastPatch= _PatchDirectory+NLMISC::CFile::getFilenameWithoutExtension(prevVersionFileName)+".patch";
-				if (NLMISC::CFile::fileExists(lastPatch.c_str()))
+				if (NLMISC::CFile::getFilename(lastPatch.c_str()) != "nul.patch" && NLMISC::CFile::fileExists(lastPatch.c_str()))
 					NLMISC::CFile::deleteFile(lastPatch.c_str());
 			}