I’m having the same issue as what appears to be listed here:
https://issues.civicrm.org/jira/browse/CRM-17864
I get the same "Network Error" message every time I press the CiviCRM button on the WordPress 'new page' screen when using Chome, FF, and Safari. Perhaps it is an admin or setup error on my part, and not a CiviCRM issue.
I took a screen shot that includes the browser console log if it might be helpful.