diff --git a/bin/fail2ban-testcases b/bin/fail2ban-testcases
index 34d392e4..7e5f7aca 100755
--- a/bin/fail2ban-testcases
+++ b/bin/fail2ban-testcases
@@ -45,7 +45,11 @@ from fail2ban.server.mytime import MyTime
 from optparse import OptionParser, Option
 
 # Update fail2ban-python env to current python version (where f2b-modules located/installed)
-updatePyExec(os.path.dirname(__file__))
+bindir = os.path.dirname(
+	# __file__ seems to be overwritten sometimes on some python versions (e.g. bug of 2.6 by running under cProfile, etc.):
+	sys.argv[0] if os.path.basename(sys.argv[0]) == 'fail2ban-testcases' else __file__
+)
+updatePyExec(bindir)
 
 def get_opt_parser():
 	# use module docstring for help output
diff --git a/setup.py b/setup.py
index be1fe685..11d0a20b 100755
--- a/setup.py
+++ b/setup.py
@@ -66,7 +66,11 @@ class install_scripts_f2b(install_scripts):
 
 
 # Update fail2ban-python env to current python version (where f2b-modules located/installed)
-updatePyExec(os.path.join(os.path.dirname(__file__), 'bin'))
+rootdir = os.path.realpath(os.path.dirname(
+	# __file__ seems to be overwritten sometimes on some python versions (e.g. bug of 2.6 by running under cProfile, etc.):
+	sys.argv[0] if os.path.basename(sys.argv[0]) == 'setup.py' else __file__
+))
+updatePyExec(os.path.join(rootdir, 'bin'))
 
 if setuptools and "test" in sys.argv:
 	import logging