1. For problems with the RUNSYSIN; check the log for messages and look at where startup ends - if it gets that far.
2. For problems with the VTAM ACB; the ACB must be in CNCT status prior to starting the region.
You can also try varying the major node INACT then ACT to see if that resolves the problem.
3. For problems with data sets - check the output of the very first failed startup.
There should be messages in there indicating which files are archived.
If nothing shows up, you can check all SOLVE datasets in TSO 3.4 and verify that they are available on DASD.
If your problem persists after checking these items, please contact support for assistance and supply the complete output from your SOLVE task.