diff -r d8fccb2cd802 -r 468f4c8d3d5b Orb/Doxygen/src/portable.cpp
--- a/Orb/Doxygen/src/portable.cpp	Fri Apr 23 20:47:58 2010 +0100
+++ b/Orb/Doxygen/src/portable.cpp	Wed Aug 11 14:49:30 2010 +0100
@@ -179,6 +179,7 @@
 
 void portable_setenv(const char *name,const char *value)
 {
+    if (value==0) value="";
 #if defined(_WIN32) && !defined(__CYGWIN__)
     SetEnvironmentVariable(name,value);
 #else