dbb4090d_Internal_Error_Codes___DocWiki__Descriptor
[Code] 28 [Explanation] A Tcl script tried to issue a leg setup continue' command when a previous setup continue command was still outstanding. [Category] 180 [Descriptor] 
Illegal "setup continue"
Cisco IOS Voice Troubleshooting and Monitoring -- Cisco VoIP Internal Error Codes - DocWiki