locate & updatedb - files not found
Try:

sudo /usr/libexec/locate.updatedb


And look config:

/etc/locate.rc           the configuration file

Edited:

Post here output:

echo $LOCATE_CONFIG


And:

cat /etc/locate.rc


And:

echo $0


Update:

https://developer.apple.com/library/mac/documentation/Darwin/Reference/Manpages/man1/locate.1.html#//apple_ref/doc/man/1/locate

The locate program searches a database for all pathnames which match the specified pattern.  The data-base database
     base is recomputed periodically (usually weekly or daily), and contains the pathnames of all files
     which are publicly accessible.

Try mdfind instead locate

Updated2:

mdfind -name text which is more accurate. Just mdfind text gives you files that contain text as well. –  David Krmpotic

mdfind -name text