John - The ANR8213W message is conspicuously deficient in not parenthetically including the IP address along with the network name that it's reporting, such that you don't know for certain what address the TSM server is using in making the connection attempt. With DNS awry at your location, it may be that in the last client-server interaction that an address was obtained for the next interaction, where that address is no longer valid. IBM Technote 1296826 goes into other aspects of this situation.
I would not fault TSM in the missed schedule: I would not want my server to be interacting with dubious network addresses where supposedly secured host data is involved. Flakey DNS is a very bad situation, and needs to get permanently fixed there. If you have good Security people there, they should be railing on people about the ramifications of erroneous network addresses being given out by your DNS servers. You can look into the DNSLOOKUP option for your TSM server, but there remains the larger issue of bad addresses being given out in the environment in general. Richard Sims