diff --git a/ISM/Port.cr b/ISM/Port.cr
index ccafa0e..7a2249b 100644
--- a/ISM/Port.cr
+++ b/ISM/Port.cr
@@ -171,7 +171,7 @@ module ISM
 
             return Process.new( "git clone --depth 1 --branch=#{Ism.portsSettings.targetVersion} #{url}",
                                 shell: true,
-                                chdir: directoryPathPrefix)
+                                chdir: self.class.directoryPathPrefix)
 
             rescue error
                 Ism.printSystemCallErrorNotification(error)