diff --git a/trimsp/src/TrimSPGUI/INSTALL b/trimsp/src/TrimSPGUI/INSTALL
index 9e2b535..a8b0f55 100644
--- a/trimsp/src/TrimSPGUI/INSTALL
+++ b/trimsp/src/TrimSPGUI/INSTALL
@@ -18,6 +18,17 @@ notest install GGARAND/PerlQt-3.008.tar.gz
 
 2) By installing PerlQt3 from source: http://search.cpan.org/CPAN/authors/id/G/GG/GGARAND/PerlQt-3.008.tar.gz
 
+Likely you need to define
+
+$ export CXXFLAGS=-fPIC
+
+before you can call 
+
+$ perl Makefile.PL 
+
+on 64-bit systems.
+
+3) adopted the paths in TrimSP.
 
 Now, you are ready to run the GUI. For questions and support please
 constact Zaher Salman <zaher.salman@psi.ch>