Help plz !! Can anyone explain to me this message?

[iimene]

HI!
Ii'm trying to install ns 2.33 on fedora but after /. validate
this message appears
---------------------------------------------------------------
These messages are NOT errors and can be ignored:
    warning: using backward compatibility mode
    This test is not implemented in backward compatibility mode


validate overall report: some portable tests failed:
     ./test-all-red
to re-run a specific test, cd tcl/test; ./test-all-TEST-NAME
-------------------------------------------------------------
Could you plz explain to me what means and what shall I do?

thanks in advance