python blabla.py will execute. But ./blabla.py gives me an error of "no such file or directory" on CentOS6.3.
/usr/bin/env python does open up python properly.
I am new to linux and really would like to get this working. Could someone help?
Thanks in advance!

Note: thanks to all the fast replies!
I did have the #!/usr/bin/env python line at the beginning.
which python gives /usr/bin/python as an output.
And the chmod +x was done as well.
The exact error was "no such file or directory" for ./blabla.py, but python blabla.py runs fine.
Add #!/usr/bin/env python at the head of your script file.
It tell your system to search for the python interpreter and execute your script with it.
/usr/bin/env python opens up python, but ./blabla.py does not execute