Hello Chris,
have you got a supervisor in slot 5 ?
How many supervisors are in the chassis ?
IPC should stand for inter process communication and the message should complain of an high number of messages sitting in a queue waiting to be processed or dispatched.
As you have already checked this is the output from error message decoder
1. %IPC-5-WATERMARK: [dec] messages pending in [chars] for the port [chars]([hex].[hex]) seat [hex]
Several IPC messages are waiting to be processed. If the number increases, this condition may result in the exhaustion of IPC header cache or buffers.
Recommended Action: Copy the message exactly as it appears on the console or in the system log. Enter the show tech-support ipc command to gather data that may help identify the nature of the error. Research and attempt to resolve the issue using the tools and utilities provided at http://www.cisco.com/tac. With some messages, these tools and utilities will supply clarifying information. Search for resolved software issues using the Bug Toolkit at http://tools.cisco.com/Support/BugToolKit/action.do?hdnAction=searchBugs. If you still require assistance, open a case with the Technical Assistance Center via the Internet at http://www.cisco.com/cgi-bin/front.x/case_tools/caseOpen.pl, or contact your Cisco technical support representative and provide the representative with the information you have gathered. Attach the following information to your case in nonzipped, plain-text (.txt) format: the output of the show logging and show tech-support ipc commands and your pertinent troubleshooting logs.
It suggests to use
sh tech-support ipc
to get more information
Hope to help
Giuseppe
