You have incorrectly edited the files. You edited the files but did not save the changes or tried to save with files in read-only mode. You have failed to press the proper keys for console to come up. Depending on OS language and keyboard, special buttons like Tilde may be at different places. Change the console key for something you can't miss, like the key P or so on.
For some reason, on some games, the console window does not show up for me, despite it being open. The only signal may be that suddenly keyboard commands do not move the character, open inventory etc. In this case, the codes and commands usually still work as long as you input them correctly. You may be suffering from the 'invisible console' syndrome as well, but I'm not sure as I never used cheats in Mass Effect.
If these don't work and you are set on cheating still, try various trainers. Beware of viruses and trojans however.