Our Advanced search proximity plugin for JomSocial works out of the box. You just need to enter you Google maps API key in plugin parameter. You may have to change Address related field labels if you have different fields labels than the default JomSocial ones. Please keep in mind that you need to enter field labels in parameters for Address, City, State etc. fields. Do not enter JomSocial field name constants. For example enter "Address" (without quotes) instead of FIELD_ADDRESS.
Things to check:
1) API key should be correct. If you have domain http://www.mydomain.com then the best way is to get a key for http://mydomain.com (without www)
2) Enter field label in parameter fields like, Address, City, State etc. DO NOT enter fields names like FIELD_ADDRESS, FIELD_CITY etc.
3) Our plugs adds a few lines in joomla core file
/libraries/joomla/database/database.php
This file should be writeable. Normall, this works with default permission of 644 but if you have a unique setup of permissions on server, you many need to chmod this file temporarily to 777. You can revert back its permission setting to your original ones after the plugin starts working.
4) If you have existing records in your JomSocial users before installation of this plugin then you need to geocode them once. After that they will appear in your search. This is required only for one time. All new additions or edits will be automatically handled by the plugin. Following is the url to geo-code existing users:
http://<yourdomain>/index.php?option=com_community&geocodeall=1
5) Contact us if it does not work still after this.