I agree with Bertrand, your problem is with using "path" as a variable. Some words have a special meaning to applescript and can't be used as a variable, path being one of them. You'll notice that when you compile your code that path doesn't turn green like other variables indicating it's special.
If you still wanted to use "path" as the variable you can though. In applescript you can put "|" around the variable to indicate to applescript that it is a variable. So this would work.
try
set short_name to do shell script "whoami"
set |path| to "afp://fileserver.local/Faculty/" & short_name
mount volume |path| as user name short_name
end try
Note that using this technique you can actually have one variable in several words like...
set |the path| to "afp://fileserver.local/Faculty/" & short_name
One last comment... there is an applescript method to get the short user name of a person...
set short_name to short user name of (get system info)