We have been having an issue with a Vista Ultimate desktop cutting off
its shared folders from the other computer. Only a reboot fixes it and
Vista will not complete a shutdown and has to be powered off.

We are getting the following error message each time this happens. Any
idea how to fix this problem?

Event ID: 4226
TCP/IP has reached the security limit imposed on the number of concurrent
TCP connect attempts.

It is possible that something else is wrong and the above error is just a
symptom.