Hello,
Just to make sure, you did close and then restart the terminal before running the commands? Next, my guess is that your system is finding a profile other than the one where you placed the path to blast.
If you cd into your home directory and type "ls -a" without quotes this will display all of your files (including the hidden ones) if you see a ".bash_profile" or ".bash_rc" add the blastall path to one of those, mac will by default only read the ".profile" file if the other two aren't in there. If you have both use the .bash_profile. Restart your terminal and see if it worked.
Hope this helps!
John