diff --git a/matlab/dynare_config.m b/matlab/dynare_config.m
index e92b63402ca16b8622a4348ca3385ed632d25bff..2a4150c5fb35931dc0dfbb311bfae683ac5329d3 100644
--- a/matlab/dynare_config.m
+++ b/matlab/dynare_config.m
@@ -76,7 +76,7 @@ if exist('OCTAVE_VERSION')
 else
     if matlab_ver_less_than('7.5')
         path_to_mex_files = [dynareroot '../mex/2007a/'] ;
-    elseif matlab_ver_less_than('7.8') || ~regexp(computer, '.*64')
+    elseif matlab_ver_less_than('7.8') || isempty(regexp(computer, '.*64', 'ONCE'))
         path_to_mex_files = [dynareroot '../mex/2007b/'] ;
     else
         path_to_mex_files = [dynareroot '../mex/2009a-64bit/'] ;