Cause:
These error messages mean that particular .CAB files are being blocked from downloading, or are timing out when downloading.

Change:
Changes have been made to network security.

Solution:

See bullet points below for resolving Error 05:

• Manually install the plug-in from the Support page of the Webex website. 
  • See article: WBX21270 - How Do I Download the Webex Client?.
     
• Network security may be blocking parts of the software download.  This can be tested by bypassing the network security, or using an alternate connection.     
  • See article: WBX264 - How Do I Allow Webex Meetings Traffic on My Network?
• If using Internet Explorer, add Webex as a trusted site.
  • See article: WBX22063 - How Do I Add Webex to Trusted Sites in Microsoft Internet Explorer?
     
• If using a Satellite connection, the Windows TCP settings may need to be modified. This can be done by directly modifying the Windows registry or by using a tool with a Graphical User Interface (GUI) such as Dr. TCP.  For more information on how to modify and what settings to use, go to: http://www.broadbandreports.com/faq/satellite.  (Note that this site is not affiliated with Webex Communications.)